> Almost all video streaming services will downgrade the stream quality if they get a 1.5Mbps pipe, and any that don't are at a competitive disadvantage to anyone who is streaming from a phone and who actually only has a 1.5Mbps pipe.

Yep, and this actually has some really annoying side effects for people with a lot of bandwidth but a low data cap. A lot of services have ways to manually control it, but some are surprisingly obtuse about it (Netflix).