So could literally anyone who writes and distributes end-point software that encrypts and/or decrypts content (or hosts software that does) - including operating systems, browsers, e2e messaging apps, password managers, VPN clients, etc.

I believe solving this problem is the crux of the next major breakthrough (if it ever comes) in privacy and personal security. I'm not even sure a solution exists, but a lot can happen when smart people put their heads together on a seemingly intractable problem.