The bigger benefit is making them easily repairable. This HAS been done, older thinkpads stayed in service way way longer than most of their comparable laptops simply because they were so serviceable.

One thing the framework does right is their charger setup- you are likely to break and wear out the charging port on a modern laptop- and when that happens on a framework you simply swap out the module and keep going. This is a much bigger deal than replaceable / upgradable motherboards, but keeping it all compatible makes parts easier to source for those repairing, not upgrading. (I’ve seen plenty of laptops discarded for a bad charging port, making it repairable without even opening up the laptop is AMAZING. I no longer have a modern thinkpad because they went to a delicate usb-c directly soldered to the motherboard instead of the old wired in charging port that you could repair by unplugging the broken one)

They're still doing miles better than a typical laptop company. If you bought a HP or Dell or Apple and you wanted an upgrade, your only options are to sell it second hand or throw it away. Framework provides a third option of repurposing the mainboard, should you wish to so, plus it creates less e-waste because the screen, keyboard, battery, chassis etc. don't have to be replaced if they're working fine

The draw has always been that if any component breaks, you can just replace it. Most laptops make you replace the whole screen assembly if the screen breaks. Here you can just buy the screen, or the fan and heatsink, or the hinge, or literally any component that breaks. And the whole thing can be disassembled by the screwdriver they package with it, no glued parts to pry apart. They aren't doing it to get rich, they're doing it to make a revolution. Oh yeah, and you can upgrade the CPU too.