I think the ballooning vintage Japanese population reports reflect what you are saying, that the mint and gem mint cards are finding their way oversees to PSA and what is left on the Japanese mainland is increasingly NM, LP, or Played.
I also wanted to highlight this auction that took place on Goldin last night, ending at $20,483 (<$10 per card):
I hope so. This must be what stock nerds felt like with the AMC and GME wave a few years ago (still going?). To that point, I’m selling modern high popularity modern, and buying cheaper modern and vintage I love while I still can. I just posted 8 cards today and reached my monthly eBay limit. I’m hoping modern is dragging people in and leading them to expand the whole market with vintage included. Some of these modern Japanese hurt to sell, but when you’re getting 500%+ ROI on some it’s hard to hold.
This hits at a point and a poll I wanted to create, but I’m still deciding and working on the formulation. Intersting that you also mentioned it… Very intersting. 
I VERY safe distance. 
Yeah! Keep spreading the word!
…at least when I’m still buying them!
I feel like it would have happened by now if it was going to
To be fair, I wish I saw that auction as I would have snapped it up at that price.
The condition of the cards is pretty meh though.
Still 2100 cards 
…