A show about the invention of the replicator and how it changes the world would be fascinating. Evil corporations and dictatorships could provide the conflict.
But it wouldn't be Star Trek
. I watch the show because I want to see spaceships and aliens and weird shit going on out in the cosmos.
Star Trek was a show that was supposed to show us society's issues through a big layer of make-up and special effects. But that make-up, those effects, they weren't what the show was about. And that's why I personally feel that a show set a few years after First Contact, showing how humanity is leaving things like racial issues, global war, poverty and general useless behaviour we find so fantastic these days behind them.