(puts on my job hat)
There are legal, regulated, functional electronic payment methods that bypass credit card processors entirely. They are largely electronic variations of traditional paper checks - direct bank account to bank account transfers - often (but not always) with a 3rd party service provider in the middle handling the details.
In the USA, ACH is the big one. it's slow, outdated, and terrible in all sorts of ways, but it works, and has very low transaction costs. Most of the rest of the world has better, faster, and more modern systems for direct bank account transfers, and the USA is slowly building one of our own.
A single artist couldn't just start accepting ACH payments, but a platform that wanted to serve a niche of artists could absolutely set up an ACH payment channel as an alternative to credit/debit cards. It's also possible that "self hosting" direct transfer payments might be possible with some of the more modern transfer methods available for other currencies today, or that it will be possible with dollars in the future once the USA's fast transfer system is up and running. Not sure.
Even with all that, ACH today is a far more viable alternative than crypto. The pipes are right there, they work, and they move millions (if not billions) of dollars around every single day. Crypto is a speculative asset class with high volatility and tremendous transaction costs. The only things people actually buy with crypto are crimes and other crypto.