Bluegrass venues used to be the last holdout for acoustic instruments being played into mics. You would never see a plugged in guitar at a bluegrass festival, then, sometime in the eighties, someone convinced Doc Watson to plug in. I had heard Doc a few times and was a real fan, but the first time I heard him plugged (Pinnacle Hill BG Festival in Renfrew, Ontario?) it sounded terrible. This is not just my opinion, it was the topic of conversation at the festival. He played the same, but his guitar sounded quacky and twangy, not the lovely sound we'd gotten used to.
Tony Rice in an interview: "Any interviewer who asks me what type of pickup I use, has never seen one of my shows."
Gillian Welsh, John Hammond Jr., Country Joe MacDonald, David Rawlings. . . all play through mics and forgo using pickups (or they did last time I saw them) and they sound wonderful.

I will admit that I have pickups in my guitars and do resort to using them when I am playing in a group with drums or when the rest of the group has pickups, but this is purely out of self defense and I really miss being able to "play the mic" (-move in close for solos and step back for rhythm, the way I do with my voice)
I've also noticed that the days of the 5 minute sound check seem to be gone, but the overall sound has not improved over the sixties when no one plugged in.