I know a poet. Very good. His day job is working as a roofer and this supplies him with much of his material. He started doing performances, got known regionally. His roofing job needed him, he messed them about once or twice. The boss says eventually, you need to choose if you're working for me or not. They are a team, right? He chooses the poetry. But did this necessarily liberate his Muse or not? The job provided him with much of his material. To know you can pay the bills is also liberating. I know a number of folk who thought, aha, I am about to break through, and they ditched the day job, but still, for all the bigging up, 'it' didn't happen. Not because they weren't good, or even, very good, but such are the vagaries of Arts Council funding on the one hand (this is a huge 'scene' in the UK, specially for poetry, and it's cliquey as hell) and the open publishing market on the other.
There is another category, paid professional artist or writer, that stops short of 'career'. They do their own thing artistically, but don't resent the job that pays the bills. Sure, it takes up time and energy, but it frees them of worry about the basics, and also, as the saying goes, if you want a job done, give it to a busy person.
It's pressure, external as well as internal, not absence of pressure that creates a diamond.