no new company should take its own payments?
However, I've heard (too) many stories like "our payments/ads/infra vendor banned us out of the blue for suspicion/politics/obscure-AI-decision" to ignore this. It could be fine for a start-up that is inherently risky, intended to fail early and risks Other-People's-Money (TM), but not always.
But yes, the fact that essentially all payments are bottlenecked through two vendors with no legal supervision is quite troubling.
Maybe we should form a co-operative of payment recipients? It doesn't need to operate anything, but rather be a "suicide pact" that will extoll a high price from payment processors if they try to unfairly ban a business. Some sort of a smart contract could guarantee fair enforcement.