If Steam not hosting your game causes your studio to shut down, it’s not because Steam is being some unreasonable gatekeeper. It’s because you’re making something that there isn’t any market for, or so little of a market that your only hope is to get it visible to as many people as possible so the tiny fraction of them that are interested can keep you afloat.
You know being on Steam means crucial access to more customers. To most customers, in fact.
The games that do well, despite being invisible to the supermajority of customers, are the exceptions. Nobody gets dropped from EGS or Itch and goes "oh no, we're ruined, we're only on Steam now." But the opposite happens repeatedly. The reason is not complicated.