The first thing to consider is that what the internet considers as truth and myth, including your and my opinion of it, is completely beside the point. Paul has shown repeatedly that he is willing to go with, against, and sideways over the grain of conventional wisdom and opinion with just one thing in mind: a better guitar. When he does something, whether I agree with it or not (and there have been both), I have seen enough in 15-ish years of playing PRS guitars to believe that
he thinks it betters the instrument.
If the quality of a guitar wasn’t an integral part of the magic of creating music, there wouldn’t be virtuosic writers and players who are known for playing a particular guitar.
Of course the guitar is a big part of the sound. Not as big as the person playing it, but it’s the only part they’re touching!
There are quite a few videos where Paul talks about finish type and thickness affecting the tone, and why they have changed to one or the other over time. One from 2013 talking about the V12 finish (IIRC) is here:
Obviously there’s been more changes to the finish, but the concept of changing it because
in the opinion of Paul Reed Smith and his luthiers it makes a better, more resonant guitar is apparent. Nothing would be easier and cheaper than never changing. They change to evolve. Not every choice is golden, but their popularity says they have a winning percentage at the plate. Paul has no reason to “suck up” to a guitar company that has a reputation for sketchy quality in this day and age, although they are hopefully on an upswing there now.
There are more, and more recent, videos on the current finishes and why they use them. But the end reason is always the same: to improve.
I, like you apparently, did my first paying gigs back in the 1970s. I was a dedicated Gibson guy. Then played Carvins, Fenders, EBMMs, Yamahas over the years and still own many. But for a lot of years now, it’s been PRS. For me, it matters. By every indication I’ve seen, it matters to Paul. I’m not onboard with everything he thinks, but I’m certainly on board with the passion that takes him there. YMMV, as they say, and there are always going to be other guitar makers who “make it your way.” That’s a plus for us. I wouldn’t infer the man has bad motives for it, because there’s no basis to go down that road.