Keeping memory alive is how sleep worked for over a decade and is incredibly power efficient.

The issue is that Modern Standby goes ones step further and keeps the CPU and peripherals in low power states instead of just the memory. This will use more power than S3 sleep by default, and each SoC will need deep integration with the kernel for that to ever be power efficient. That means it will require heavy investment from AMD and Intel to enable efficient Modern Standby in Linux, along with heavy vendor investment to ensure each model they sell implements Modern Standby efficiently.

It isn't a matter of Framework dropping the ball, it's matter of hardware platforms being shitty and platform owners not investing as much resources into Linux as they do Windows.