I think the allure for many Vintage players was a stagnant metagame and the opportunity to play with cards of their youth, or familiar cards of duration.
The sets of the last 3+ years have been so powerful, that almost every other set, some Vintage stalwart is being pushed out by a newer, less familiar card. It's a changing of the guard. Just look at some of the most powerful cards in decks right now: PO, Inspector, Mentor, Hangarback, Ballista, Hollow One. That's a lot of old frame cards being replaced by new frames.
For some players, the new and exciting cards are interesting and inspiring.
For other players, seeing a card like Triskelion or Mana Drain become obsolete is upsetting. That portion of the metagame (for now) has gone to Old School.