Don't you find it just a bit mysterious how a site that already works perfectly well and does a technically pretty basic task can spend that kind of money?

The answer would still be interesting for those for whom it's not obvious. I include myself among those people.

* overhead - people cost a lot of money: this includes ongoing maintenance of the tech stack, including rewrites of obsolete parts, but also ops cost - preprinting can include more than one human touchpoint

* converting PDFs to HTML is an annoying problem

* searchability of the repo is likely an annoying problem

* any new features that stakeholders want added (commenting, annotations, etc) * ongoing hosting / CDN cost

How much do each of those cost and how does it add up to 10M? If you get two overqualified people to work on it full time and pay them FAANG salaries it'll still be enough for decades. I can't imagine the hosting is expensive when 99% of the papers are a few megs at most.

I'm just a bit confused because this is a site that already works really well and isn't technically difficult.