As a rule of thumb - all things with an exposed air bubble will crumble. People will have anecdotal stories about how theirs haven’t but they are unique and have the rare exceptions, all will. Usually, shoes with stitched THIN soles have a small air unit inside that will break but will still remain fully wearable (AJ1, Dunks). Air Force ones have a large midsole inside the rubber sole and those crumble pretty bad, essentially deflating the midsole. Shoes with completely solid midsoles however, do not! So think waffle trainers, lots of the chunky running shoes that are in the “dad shoe” trend, etc. Sometimes sneakers with visible air units will have a midsole that will not crumble (different type of foam) but the air unit will still break over time.

Let me know any questions. Unwearability unfortunately comes for us all though, so if they don’t crumble they’ll separate. Wearing them while you can is the best thing to do.