@DoctorAction - I think you're underrating what having a consistent tempo *does* do to make music feel better. When you setup effects you program them to breathe/pulse with the tempo of the music. If you hear a kick drum and it feels like the whole song is breathing with the kick drum, it's due to that kind of effects programming. If you don't have a consistent tempo this kind of mixing is harder to do because then the effects are at risk of clashing with the rhythm of the music.
Also, for an audio engineer, everything they need to do is easier if they know they can work from a grid. Not just in terms of splicing takes, but automating the volume levels in the mix. I know that professionals can do these rote tasks so quickly it looks like magic, but still no need to waste their time.
The one thing where I do agree with you is I think it's risky to overly-quantize. It gets rid of the little imperfections in the drumming that make it feel human. Not a human example, but I remember Mangini talking about how on DT12 he was trying to play as on-tempo and as evenly as possible for the sake of the recording. I think his playing (in spite of some good beats) suffers on that album as a result. On the new album it feels like he's loosened up a bit and you can feel his energy come through better as a result.
I'll also admit I'm not really interested in recorded music being or feeling spontaneous. The recording studio is an environment where you can achieve perfection through technology and repeated takes. I see no reason not to play to those strengths as much as possible. If I want spontaneity I'll listen to live music (I don't love DT using a click track live for this reason).
Yes there are edge cases that you can't handle with a metronome/quantization, but for 99% of music these tools are fine as long as they are used properly.
Back then they also didn't have the capability to visually see the tempo or the wave file itself. They had to make do with hearing. We also have to wonder if some of these intricacies are not tape splicing intricacies of taping the analogue overdubs together and just being off a slight bit.
I've never heard of something like this happening. The old tape splicers were masters of making things feel natural.
Ironically, this is an area where modern technology has hurt (though no fault of its own). If you do a digital splice improperly you can hear the audio clip, which I don't think was ever an issue with tape. A simple crossfade can solve this issue, but I still hear clips more often than I should (which is never).