Without subversive profit incentives, the incentives become to make necessary-but-undesirable jobs more safe/pleasant/automated. Without worrying about their next paycheque, people can spend time on the issue.

This requires a post-scarcity society that is fairly well developed, before they try to convert to communism.

I wouldn't necessarily say that capitalism pays dangerous or unpleasant jobs well, though. Some do, but lots don't.