I've spent just over 1k crests this campaign (started at 2k and just under 1k now) and I have 1 stack of hmp and 6 pouches.
With one character? Or several? Because that is crazy. Either I'm super unlucky, or the game loves you guys.
Edit: Doing the math on this. If you used 1k crests on one character, that is 50 fights, and you can only ever get 1 single plate per fight (not guaranteed), so I can't see how you got over a stack with that many fights. You must have done way more than 100 fights to get that many singles. Unless you popped some pouches, or already had close to a stack before starting.
Edit2: And as I say this I get two HM pouches in 3 fights. Go figure, lol.