That might be why Sam Altman signed it but why do you think that all the academics did so as well. Do you think he just bribed them all or something?
Just because you can do fancy math doesn't mean you understand how to play the game.
https://www.npr.org/sections/thetwo-way/2016/09/13/493739074...
That motivation being that all their current research fiefdoms are now outdated/worthless.