There's a difference between awesome projects that don't have a recurring cost (i.e. open source software that users run themselves) and a search engine. You cannot physically run a search engine without real-world costs today. Those funds need to come from somewhere. And offering a good product at scale costs a lot of money.

That is very true, and it's not cheap to maintain. I do however really hope that donations can cover it enough, and I have plans about other ways to monetise it while remaining not-for-profit without ads or anything that affects the user.

Just brainstorming here, but would a distributed search index be possible / usable with current network speeds and latency? I'm not sure how to set up the data structure to not require many high latency jumps, but maybe someone has solved this problem.