A bank may offer a loan, which can be a lot of help in some situations, but a bank is not your business partner.
Think about a bank for a second, if Bank of America loans an indie game 100k and even stands to make double that, 100k in interest. Do you think BofA cares about that amount of money? To me personally, 100k is a lot of money, but to BofA, it's not even "get out of bed" money. If you've seen the "Big Short," there is a scene where some hedge fund with 10/100 million in the bank wants to be one of the big guys and the bank says you'll need ten times that much to be considered. Do you think the guy who is issuing the loan really cares either? She or he does not work on commission, so there is no upside for this person. On the one hand your business fails, at which point, the bank loses money, and the loan officer looks bad. On the other hand, your business takes off and the bank makes such a small amount of money that the bank does not care at all, and the loan officer who decides gets zero dollars for the effort.
Same thing with Steam. Let's say your game sells 100k copies. This would be a major accomplishment for me personally and my company, but from steam's point of view, that's about 300k of income for them? That is nothing compared to the billions of dollars they take in every year. It's less than 1% of their income. I think less than .1% of their income?
To make a bona fide business partnership, there needs to be a shared risk, and a shared reward. The reason Steam is not your (or my) business partner is that Steam is taking no risk, and it has no reason that your success means Steam's success. They have tons of games, and if yours doesn't sell Steam does not care.
There can be no partnership with a 100ft big spoon and a 2-inch small spoon. It doesn't work.
So, if you are posting your game on steam, as always, you might as well just post it on your own website.