Oh yes, recording wet and dry was probably not a common situation because of the restrictions, including track count.
I think, in the cases where crazy effects were used (Beatles, Pink Floyd, Eno, etc.) those people were either quite experienced in how those effects would fit (or could be made to fit) into the mix, or were prepared (and well financed enough) to experiment.
In those cases, the crazy effect was a deliberate production decision and a key part of the tone. So I agree, that this sort of thing should definitely be a deliberate decision. Often these were physical effects (like playing through a speaker into a tube and recording the result).
But, once that artistic decision has been made, it’s something that (in the old school approach) should be committed to, which normally means tracking the crazy effect up front. If only because applying it at the mixing stage was difficult and would usually degrade the quality and burn valuable tracks.
Not to mention the guitarists would often push back against DI recording because “mah tone” (of course, that still happens).
I think another key difference is that a lot of early recordings were all mono and, as stereo became more popular, the natural evolution was to take mono tracks and mix mono sources to stereo, and this was probably better suited to the equipment of the era.
Times have changed, and stereo sources are now more common and I, personally, don’t see a problem with tracking and mixing them, especially with modern DAWs.
Even in the old days, tracking stereo sources was pretty common for some sources such as drums, to the point of almost being a standard technique, hailing back as far as the 1960s at least.
Cheers,
Keith