Literally nothing? Just leave it as is. There is a browser extension called Ruffle that lets you play older (AS2) Flash games, and eventually it will support newer (AS3) Flash games too.

Edit: most users won't have the Ruffle extension, so the one great thing they could do is add it to the site with a single <script> tag :)

False. Bandwidth and hosting and keeping site working is not nothing.

As long as they're breakeven keep it running? I guess that also takes employees and not many are interested in just maintaining a website

I never heard of the site until now, how hard would it be to convert it to static?

Flash games are static content (except for high scores). A Flash game is just a SWF file, typically a couple MB (or KB!).

If you'd like to experience the games that were available on Miniclip back in the day, your best bet is FlashPoint, a big offline archive of Flash games (ships with integrated FlashPlayer and a nice UI to search for games).

https://bluemaxima.org/flashpoint/

Someone’s already been working on it.

https://bluemaxima.org/flashpoint/