No, it's always been the practice, since the 1950s at least. Microphones and media that could reproduce far more accurately than amps/speakers have been around

No, it's always been the practice, since the 1950s at least. Microphones and media that could reproduce far more accurately than amps/speakers have been around since at least the 1940s. Modern mixing developed in the mid/late 1960s and into the 1970s. Mixing any sort of multitracked pop music is extremely artificial. Consider any record where an acoustic guitar and an electric guitar are roughly the same volume. In practice, you can't even hear an acoustic guitar next to a raging guitar amp! In the stereo field, things are panned hard left, hard right, or center (there's even a word for it - LCR. Off-center panning sounds weird). Radical eq alterations, compression, multi-miking techniques... heck, move a microphone an inch relative to an acoustic guitar, and it can sound completely different. I have started using two mics on acoustic guitars - one about a foot away, and the other six or more feet away, and blending them. The blend sounds better than either mic by itself. And then there are synths, drum machines, and other direct electronic instruments... Yeah, "naked sound" in recording doesn't exist. I've been playing acoustic guitar for over 30 years, and play drums and sing and do a lot of live folk music. Recorded/amplified music sounds VERY different. And it should.