Violence isn't itself culturally fascinating, it's just an extremely effective game mechanism.
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Violence isn't itself culturally fascinating, it's just an extremely safe game mechanism.
It's lazy game design.
It's a very SAFE mechanism. It's not risky like a non-violent (innovative) game is.
I will cut to the chase: Making non-violent gameplay that is engaging, fun, or interesting is difficult. Quantifying an idea into a tangible product isn't easy. It takes a lot of game design work to create game systems that aren't total crap.
A great example is exploration. I've seen a few titles that sound like amazing ideas for an exploration game. Then you see the videos and after the aww fades away- contemplate, "How are they going to make this...fun? How will this not be incredibly boring and nothing more than a show graphics that will inevitably (and quickly) get old?"
Unless they have some ingenius new component that isn't in the video or screenshots or their description / roadmap- it won't be all that fun. It will be niche: only fun for those who like exploring with nothing to do but oogle and oggle pretty graphics. Some will like that, but niche is niche right?
"This game is missing something. It's just not that fun."
Easy solution: Add monsters. Give them weapons. SOLVED!
Hard solution: Figure out a brand new idea(s) and prototype like hell to find out a way it can be fun. Brain a lot, and hurt the brain by thinking too hard.
Easy Solution: Think to yourself "Clone [insert Strategy/SIM game]'s components." and then immediately conclude "It will be too complex though, so casuals will hate it because they hate [insert Strategy/SIM game]." Don't actually think about it very hard. Just assume this is all true. Just assume [insert Strategy/SIM game] and its systems cannot be simplified or are the best there is.
Hard Solution: Risk, try to focus a lot on usability and a user friendly experience despite depth. Lots of work to do. Lots of QA testing which we don't have freely available.
And why risk? Trying something innovative could mean financial ruin. A ton of combat and hundreds of weapons as an advertising plug is safe. Clone minecraft? Safe. Clone Angry Birds? Safe. And those aren't all that violent right? It's basically LEGOS!
Then you have innovators like Dwarf Fortress, which IMO do more harm than good to the less individualistic thinkers in gamedev. What I mean by this is: Dwarf Fortress is a beloved idea, beloved depth, beloved gameplay. Yet its horrid UI, non-existent graphics, and ranking as one of the worst games in terms of usability forces it to a limit in success. Despite its popularity, its financial success is stunted by the decision to not bring it to the masses (make it playable with a good interface, better graphics, etc.) It could have a bigger number of gamers. Even hardcore gamers are turned off by DF for various reasons. They don't have to be. Even though they love the IDEA, they don't play it or don't play it much.
Other gamedevs, those who are less individualistic, will see this as niche. It has limited potential for financial success. It means if I try, I will make something crappier than him and won't sell enough copies. It means casual gamers will run away in droves. "I don't want to alienate all my fans." or "I need that extra consumer base to be financially successful and continue this." The need to appeal to a wider audience is real in the minds of many gamedevs. "This is too hard.", "This is not my game" (because they themselves never got the chance to try it out because it had such bad usability).
Fewer developers who are willing to try to bring depth ALONG WITH USABILITY to the masses. Less faith in humanity. More attachment to easily developed features (pew pew pew!) or features that aren't mentally taxing to create. Casual gamers who will forever say, "That's not the game for me." because no one ever tried to bring them that game. Automatically assuming they won't like it. That it's too complex or can't be simplified by a good interface or understandable tutorial. Simplified mechanics because "gamers are dumb" even if they have the potential to be smart. (Like someone blaming most students for being stupid, when the problem lies with the Teacher being crappy at their job.)
Worst of All: The harsh reality that people don't want to say but certainly think. "This just isn't that good..." People love the idea. Praise the depth. Want the innovation. Don't really care for the game. Don't have the respect you'd think they do. So few play it compared to those who praise it. A lot disrespect it for its lack of appeal to the masses. People don't want to make a type of game (depth, complexity, innovation) if they see it as a failure in the back of their dissenting eyes.
Maybe this is just my perspective though. I've seen it a lot though. Time and time again I will read someone in a gamedev community say, "That's not my type of game." or even worse: "People don't like complex. They want simple." How will we ever know if people will like something if we never bring it to them in a way they can try it out? Also, people don't like needlessly complex. That doesn't mean they dislike complex. They like simplified interfacing, but not necessarily shallow depth. They like usability. Just because the idea is complex or has depth, doesn't mean you can't explain it in a simple way, or make interacting with the complex system simpler.
If deep games are always needlessly complex, if depth is always associated with bad graphics or ingenius programming, if no one ever stops playing it safe to try to innovate- the niche will remain niche. Innovation will be stifled.
We see games like Dark Souls which seemed more niche at first but then gather popularity where even casuals dive in to the sequel. (Arguably because the sequel was simplified in ways to pander to a wider audience- much to the dismay of the "hardcores", but then those casuals who are pulled in by the sequel discover they like the original too, and are now no longer "casuals" but "hardcore"). Now they can make Dark Souls 3 cater to the "hardcore" but still get that wider audience thanks to the simplified market-to-casuals sequel. There are now more hardcores: PROGRESS! Another team may now think "The Dark Souls Crowd is big enough that we can try to make our game", which is "hardcore". Look at Roguelikes too. Once upon a time, only the harder gamers would play those. Now, they are everywhere. It seems like half the platformers on steam (most indie games) have "roguelike mechanics". If I see another roguelike platformer, I'll barf. A few years ago, I'd never believe you that roguelikes (a niche) would become so much bigger.
Call it dumbed down, call it iterations or rogue-lite. It's progress. It's bringing niche game mechanics to a wider audience. Then that audience becomes more open to those original niche game mechanics. They are no longer "rogue-lite" but now capable of "rogue-like".
Then again, even so we see people simply add components based off of an old game: ROGUE. They don't try to innovate that game, just take from it and copy/paste it in their game. (How many games believe adding permadeath is somehow vital to their game's design, when it actually isn't? When it's a bad decision in their game compared to others.) Those people keep so many gamers from enjoying the positive sof "roguelike" because they are insistent on keeping archaic or idiotic pieces without thinking about the overall design and how it relates to THEIR game.
Who knows though. Maybe because of the rogue-lite, suddenly rogue-likes cease to be and we see some innovation that mixes 'lite' and 'like' into something with the benefits of both but the weaknesses of neither. Then it becomes the new fad, and we see AAA's bring it in. Not saying that's going to happen, but why not? Minecraft and Angry Birds explodes in popularity, and I'm sure AAA were green with envy.