Static files on literally any hardware from the last 15 years on modern server software simply won't get cooked by bots. The network switch will bottleneck you before the server will. Your ephemeral port range will run out before the server will.

Bandwidth is still not free, if you cloud host.

I had a client ask me to look into why their bill spiked 5x (admittedly not by much - from a few dollars to tens). They run a static site, and it turned out someone had inadvertently replaced an image with a massive uncompressed photo. Every unique visitor was caching O(25MB) when they loaded the homepage. Also funny because now everyone has 100Mb+ internet, nobody noticed a few extra seconds on load.

There are lots of solutions to this if you actually need to serve a lot of bytes, but you can get stung even with very simple deployments. Not everyone wants to put Anubis or Cloudflare in front of their site.