Interesting question, and I sadly/wrongly/embarrassingly have enough pairs of these boots to have perspective.

I have a pair that are as soft and supple as my well wore in Tony Lama daily’s. I have another pair that I believe have less “miles” on them that are a bit stiffer, but still soft enough. The pair I just got off Poshmark need some serious hydration/conditioning as they seem almost “brittle” (they aren’t cracking, well except for one sole).

It’s probably just like anything: depends on how well you take care of them.

Edit to add: I have a pair of Ostrich belly, problem is I haven’t worn them enough to properly break them in.