It's not Apple's problem if people don't bother. Also, devs should normally receive the GM at least a week before the general public.
No its not but it is in their interest that most people don’t have products that are at risk.
The GM is done loaded on phones waiting to be dispatched.
Devs have had 8 betas to get ready. Same argument last year.
No reason why iOS 15 has to be delayed after tomorrow