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
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.
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.
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.
I have downloaded quite a few Linux ISOs from mirrors at 90MB/s.