My reading that the design of this structure is not to require partners to make decisions in the interest of the mission, but to remove incentives for them to make decisions against the interest of the mission. With a cap on returns, there's a point at which it stops making sense to maximize short-term value or reduce expenses, and with the words about fiduciary duty, it becomes defensible to make decisions that don't obviously increase profit. That is, this structure seems much better than the traditional startup structure and I suspect many entities that are currently actual, normal startups would do more good for the world under a structure like this. (Or that many people who are bootstrapping because they have a vision and they don't want VCs to force them into short-term decisions could productively take some VC investment under this sort of model.)

I agree this isn't a non-profit any more. It seems like that's the goal: they want to raise money the way they'd be able to as a normal startup (notably, from Silicon Valley's gatekeepers who expect a return on investment), without quite turning into a normal startup. If the price for money from Silicon Valley's gatekeepers is a board seat, this is a safer sort of board seat than the normal one.

(Whether this is the only way to raise enough money for their project is an interesting question. So is whether it's a good idea to give even indirect, limited control of Friendly AI to Silicon Valley's gatekeepers - even if they're not motivated by profit and only influencing it with their long-term desires for the mission, it's still unclear that the coherent extrapolated volition of the Altmans and Khoslas of the world is aligned with the coherent extrapolated volition of humanity at large.)