What's more important, Supply or Demand?

[mintacular]

I've always favored vintage for many reasons, one of them being that the "supply" was limited so the cards were a safer investment. Yet, recent trends suggest that when I got back into the hobby 15 or so years ago had I bought MJ rookies, PSA 10 UD Griffey's, any Lebron's, etc, I would have done much better (from a financial standpoint) compared with various Clemente, Mantle's, other rookies from the vintage years....

While these mainstay classics have ticked up over the years, never have they exploded like the aforementioned..... That said, from a collecting perspective, I have no regrets-- let me be clear... But were my assumptions all wrong? Did I focus too much on supply and minimize the demand portion? Or is the current frenzy of high grade base rookies a passing faze?

The catalyst to challenging my original mindset is the PSA 7 Jordan RC I own that has gone from $850 when I bought it in 2017? to 4K?-ish or so now while my other vintage stars have just crept up slowly in value. Mind you, the Jordan card is a VAST exception in a narrow window of excitement (due to the "Last Dance") perhaps, or is it? And also, should come back to earth....or will it?