I have a couple generation back amd laptop that can 'standby' for months.. its called S4 hibernate. Although at the same time its set for S3 and can sit in S3 for a few days at least and recover in less time than it takes to open the screen. The idea that you need instant wakeup when the screen has been closed for days is sorta a niche case, even apple's machines hibernate if you leave the screen closed for too long.

That isn't to say that modern standby/s2-idle isn't super useful, because it is, but more for actual use cases where the machine can basically go to sleep with the screen on displaying something the user is interacting with.