Are you likely to succeed after this point?
At this point getting on Steam doesn't guarantee any success. But in most cases, you still need to be on Steam if you want to be successful. It is by far the largest game distribution platform out there and even though it's accepting more games than ever, and it's much easier to get buried there now, it's still almost essential to get on there if you want to make any real money off of your game. It's just now easier to get on there, and more difficult to become successful once you are on there.
Of course there are other ways of becoming successful, in theory. You may be able to get to enough people to buy your game directly off your own site, for example. But that too, is one big popularity contest (responding to Constan7ine's observation). That's what marketing is really, any way you look at it, it's a numbers game. The only way to become successful is to sell a whole lot of copies of your game. And the chances of that are significantly increased if you're able to get on Steam because it's just so large and has so many users (meaning potential customers).