It took years to put band-aid security measures onto a standard that initially allowed random websites to dump your VRAM contents and/or remotely exploit kernel

It took years to put band-aid security measures onto a standard that initially allowed random websites to dump your VRAM contents and/or remotely exploit kernel-layer video driver bugs. And graphics drivers/hardware are a much easier to control market than USB devices. You have five or six GPU vendors to yell at and/or blacklist broken driver versions, and tens of thousands of USB vendors.