I have downloaded quite a few Linux ISOs from mirrors at 90MB/s.
I think that is more so due to overhead in writing files and most likely also doing some live decompression or some other stuff. After all it does not download single file like iso would be.
It actually isn't all that different. A lot of modern games are basically a smallish exe and a single giant Assets file that's many many GB, and is some sort of encrypyted (or not) filesystem image.
This is surprising to me: I've seen Steam peak around 1500 on my connection. Linux ISOs from cloud mirrors (like DO) can hit closer to 2gbps. Bittorrent downloads of Ubuntu ISOs sometimes hit 2gbps
That's due to your ISP's peering, not the server.
Exactly this. ISPs are tricky players when it comes to peering. A typical symptom: servers in local region/country can easily saturate the connection, when anything external gets cropped down to 20-50% of a declared full speed.
Ok, so what? Whether it is the server, the ISP, the CDN, or whatever - if I can't utilise the speed, what's the point?
Supply and demand, why would they bother improving the infrastructure if people can't use it? Either be an early adopter, and help progress or sit at the back and wait.
My experience too. For some reason the Sony servers are terrible. I'm lucky to see 100Mbps speeds, and that's on a gigabit link.
I think your local ssd cache is the only thing being saturated.