The difference is the delivery model. Internet streaming is unicast, and (correct me if I'm wrong!) Cable TV viewers are receiving multicast feeds to their neighborhoods.

OTA broadcast is also best described as multicast.

Satellite -- I don't have the fine details of how this works, but I think it's basically multicast streams your receiver is tuning into.

The fact is that internet streaming is much more convenient for users, but each user puts a measurable load on the system.

edit: I know that they're not literally multicast unless they're an IP network, but it's a good comparison

edit2: ISPs bringing CDN servers/equipment in-house is a good way to mimic other forms of TV distribution, but it is expensive as it requires bandwidth upgrades to support the constant stream of data coming into their network which their users may not ever request.