Blender dev here.
A majority (like 2/3) of the development nowadays happens through the core development team: it's around 30-40 full-time/part-time paid developers. Most are located in the Netherlands. We make an average salary that's slightly higher than the average in that sector here in our country. All of the money comes exclusivly from the Dev Fund (fund.blender.org). It's all donations, no strings attached. We say "thank you" and (if they wish) put the logo on the website.
Just to add a bit more context to this: Blender started as an "in-house" software (studio NeoGeo), written by Ton Roosendaal, in January 1994. In 1998, they founded a company (NaN) that would distribute Blender under a freemium pricing strategy (you would buy keys to unlock more features). But the base software could be downloaded for free. In 2002, that company went bankrupt. And with the help of 250,000 users, they raised enough money to buy back the rights owned by the investors to release Blender under an new licence: the GPL licence. In May of 2002, the Blender Foundation (non-profit) was created.
That's a feature, not a bug.