Assume the AGI has access to a credit card and it goes ahead and reserves itself every GPU cycle in existence so it's 1 month is turned into a day, and now we're back to being fucked.

Maybe an ongoing GPU shortage is the only thing that'll save us!

How would an AGI gain access to an unlimited credit card that immediately gives it remote access to all GPUs in the world?

It could hack into NVIDIA and AMD, compromise their firmware build machines silently, then publish a GPU vulnerability that required firmware updates.

After a couple months, turn on the backdoor.

E.g. by convincing 35% of this website's users to "subscribe" to its "service"?

¯\_(ಠ_ಠ)_/¯