S3 sleep is a solved problem and security issues around it are solved by Secure Boot and memory and disk encryption.

The issue is that firmware vendors disable S3 sleep in favor of s0ix/Modern Standby instead, which just puts hardware into low power states instead of stopping them entirely. This will inherently drain more power over time than just keeping memory powered in S3 sleep.

Modern Standby requires heavy integration with the OS to be power efficient. Turns out that takes a lot of reverse engineering because vendors will not release documentation or tune the kernel for their firmware.

Not just laptops but affects computers too. I have a brand-new Mini PC with Windows 11 and when you turn it "off" it continues to pull 6-10 watts. Not a lot but still over a year if you were to only used it minimally that's 52-83kwh or around $25-45/year at PG&E rates. Vendors are removing support for classic standby/hibernate so the only way to go to <1 watt is to pull the plug. It shouldn't be this way.