I imagine Roddenberry's intent was that by TNG, humans had "evolved", reached a level of social and personal enlightenment in general, that people didn't need greedy incentives to better themselves and society, but worked for personal satisfaction and because they wanted to contribute altruistically. Yes, its unrealistic, but that was always the point, that eventually humanity could reach "unrealistic" goals like... no longer having racism or poverty.
And I feel its obvious, but I'm sure he didn't think out the details of how things would work and try to plug any possible loopholes. Transporters are basically magic too, but people just jargon to explain it away because if we could 100% explain it, we'd actually have it now - the point is that we reach a level of technology so far beyond our own that we're able to achieve near magical feats