Honestly, they should have already cracked, years ago.
Wearing em right now. Not the way I store my shoes. The heel tabs still flexible, the midsole is still pristine. Air bubbles still clear. - I got 2004s shoes still wearable. My beaters are a pair from 2005. - The key is moisture control and maintenance wearing. Hell, my airmaxs 90s from 2007 - I still wear.
Only shoe that's fell apart on me is a pair of 2008 sbs, that I need to get reglued. But I knew it was gonna happen though, long before it happened.. just due to the materials on em. Some glues just don't stick well to certain materials (e.g. denim, canvas, 3M) and synthetic leathers crack. But my Boudreaux still holding strong. But her days are more numbered than the black flips.
But then again, it's a full time job practically trying to preserve shoes. It's a work of art, practically. I've had alot of shoes come close, but I've always been able to revive them. The key is catching things early. E.g. if you press the midsole, and it's feeling a bit soft. Or if you do a traction test and therubber on the soles slip..You gotta wear them to bring them back and let it sit out of the box. You can't reverse the process after it happens, you can only do thing before it happens. (Just some jewels of the art for you)
At this point for my 6 to 15+ year shoes, if the rubber soles crack or the heel tabs, or the air bubbles fogged up or if the shoes yellowed severely . Anything other than glue or deflating air bubbles (which I've never had) , its because I let them sit in the box too long without a maintenance wear or I didn't check on them as often as I should or I stored them lazy or improperly. I still got 7 year old icey soles...
You CAN severely slow down the aging process, but you can't do anything if they have aged. Aging can be slowed but not reversed, this applies to everything and all aspects in Life.
I'll send ya invoice and bill ya for the rest.. along with instructional videos on how to store different types of materials. Since it took me years to learn and perfect this. Alot of the knowledge came from researching this forum, thanks to the OGs who posted their tricks of the trade - pre 2008. Some of their advice worked, alot of it didn't. And I had to do some reinventing.. took a while.... the shoes that broke down - I obviously wore to the ground on first signs. Which was trail and error through various methods to figure out which methods worked.. and I wear those shoes today, as a testament to that hard work.