Then don’t buy it!This is, really my point. I don't want to buy the books, now -- had they waited a week, I would have had the new warm fuzzies over Spelljammer that I was looking forward to (since April/whenever). It's not there now, because there is a new/uynpredictable/shiny just up ahead.
Being "compatible" is fine, but it's not enough to get me to buy. If there's going to be a new/current version of something my interest in the previous one becomes that of a historian, not a player. I don't want to mix-and-match between alternate versions; that invites a particular form of system mastery that favour older players and those with more money, which I don't like. I would love it if everything in Tasha's, Xanathar's MotM etc. all remained "current" but at this point I can't expect it to -- and they're core books. The impetus for keeping settings, etc. in canon as it were is by definition less.
Aside the new phb and core books, all other new material will be roughly compatible with the current edition. There will be some glitch but overall you can stick to the current books and keep shopping new material once in a while.
but surely new classes will be more cool, and just a thin line over actual classes but I guess you can live with that.