Yes. Yes. Yes! A thousand times yes! It breaks my heart to see where Twitter is now. I really do believe that if the platform was to disappear, the Internet would be worse off. Alas, the company’s present course appears to be leading nowhere.
On the other hand, your proposal offers a glimpse of a future where Twitter’s core value is preserved. Lets not kid ourselves, turning the infrastructure of a publicly listed company into a non-profit is a gargantuan task. But, I do think it is a viable path to both saving the platform and creating new opportunities for fun and profit.