I kinda get what you’re saying about the differences in crew quality, but it’s been said that to even get into Starfleet Academy you need to pass entrance exams which both Picard and super-boy-genius Wesley Crusher didn’t accomplish on their first try. It’s one thing to say the best of the best get posted to the flagship. But the best of the best they selected from were already made up of the best of the best applicants. And even then, this is post-scarcity where people apply to the Academy because they legitimately want to, but like current times where you are almost forced to go to college for a better shot at jobs, or join the military for reasons beyond wanting to or some patriotic sense.

Yeah, Voyager was comparably a less impressive ship than Ent-D but it’s still a brand new, state of the art science ship with experimental technology. The mid-at-best officers and crew would be the ones assigned to remote outposts (not by choice), aged Miranda, Oberth, Jenolan class ships doing supply runs deep within Federation borders, and other middling assignments.