Traffic shaping can still occur as they see your data volumes and the networks your connecting to. Sure it might not be as specific to the streaming service, but it should be decently possible to identify other streaming services, and any ISP-owned one.

They can also do a reverse DNS lookup of the IP addresses that you are connecting to, since you can not hide that.

> Is this because ISP's can see DNS traffic? as it's in the clear over UDP...

Not necessarily.

It could very easily be done via IP address matching (think BGP communities that advertise specific subnets between one part of a network and another, as are typically used for optimal CDN routing etc.).