Wikipedia was the example I had in mind as well for donation based large scale funding that works. Especially if you consider how over funded the project is as they divert money into tons of side projects while still having enough money in the bank to keep up the site for decades. It makes me hopeful this can work.

I see a danger in too explosive growth. It could lead to an unhealthy rapid change of the user base. This is why I would prefer a somewhat steady growth. But you are absolutely right in that there are big opportunity costs to not making use of the collapse of other platforms. Which with the continued enshittification of social media will likely continue.

Lastly I just want to say how happy I am that healthy discussion like this one are possible around here.