How to make record albums

The Buddy Holly on MCA is the most "you are there" reissue in my collection, which includes quite a few 180gram efforts and some 45rpm reissues. I suspect that the original tapes were simply recorded live band performances, and the lack of analog processing was another key ingredient. Analog tapes have hiss and EQ problems and the more tracks and mixing the worse they get.
When I was young and worked in a recording studio this was well known and serious recording engineers tried to keep it simple. A big problem was that the "live take" of the group was not as profitable as the individual take of each performer, who began to take for granted that he could show up whenever he liked because it was just a track recording. From then on, quality took a back seat to the production costs of studio time and the convenience of all concerned.

Astralography: Nice post. I am a bit older than you, so have seen the evolution a bit longer. Put simply, recording live performances and making the result as convincing as possible was replaced (for economic reasons) by the recording culture that you describe. The technology (LP records) that allowed the mass production of high quality recordings rapidly evolved into the mass production of a substitute for a live musical event. Popular groups were created in the studio and road show performances were conjured up to replicate the recordings - a complete reversal of the definition of recording. The record BECAME the creative event.The Beatles completed the process, and this order of things seems "normal" today.
I respectfully disagree that digital sampling is at fault. The computer processing of the digital signal is the problem. A simple, unprocessed digital signal sounds as good as a similar analog signal. In fact, few people can hear any difference when an a/d converter is switched in and out of a line, but they can easily hear the difference when it is recorded to a hard drive and the retrieved.

If you want to replicate the classic Mercury sound, you might try sending the line output down a few miles of telephone wire!

"I've dealt with orchestra leaders who wanted me to use more mics and signal processing"

You are so right! Knowledge of live performances, and knowledge of recordings are unrelated. Many musicians do not "hear" the recording, they only reference the memory of the performance, and often they do that from the peculiar prospective of their position in the group. No recording can, or should, sound like the prospective from the stage.