That's a cheap project. I have seen a single developer's salary to be more than that. Considering that around a billion games were played last year in lichess.
I think you were saying it's cheap relative to the impact it has. I agree. But "holy hell that's expensive" is an entirely accurate reaction for someone who wants to fund it out of pocket.
(Gwern covers our TPU/ML infrastructure costs for around $350/mo, and I wince that I wasn't able to optimize it cheaper.)
"French taxes" is $53k, which is nearly equal to their server fees. Wow.
Props to them for however they manage to get $400k/yr for a free project with no business model, and no intended business model. (I'm serious; it's a wonderful thing for the world, and a tremendous example of what people can achieve without having a monetary focus.)