I'm not sure there is an accurate figure for such a thing to be disputed, how would this even be available? I don't think it can be argued that the Fender bass and more particularly the P Bass is the most recorded bass in history.
I haven't noticed this myself, fair enough bass guitar isn't always used in modern music in place of synth but other than that I can't agree. If anything, the way bass is mixed and processed by engineers nowadays can be much better.
What do you mean by fundamental? My reply that you quoted was in relation to the bass 'cutting through' which to me is not really what I want my bass to do at all, nor do many band leaders or engineers in my experience. To me, a fundamental instrument forms the base of the music and allows the rest of the instruments to build around it.
I think so yeah, there's just something magical about the P Bass (and to an extent the J Bass) as it can sound unremarkable on it's own, but sit perfectly in the mix. It's not an accident that engineers prefer it. A bit like the SM58 vocal mic, it's easy to work with and sounds good in the majority of settings.
Apologies for the tangent