cable has had on demand for a while, but it's not up to the streaming services.

The on demand is where the streaming services fill a need. The live TV is where they fall down. When I cut the cord, I assumed the live TV would be replaced by streaming, but in my household that didn't hold true, plus a lot of the services now greatly limit what is on-demand if you don't have the live channel.

In the end, it's all about who owns the content, and they are going to get theirs because they can (and they are the ones creating or buying all the distribution, including the streaming services). You are going to pay pretty much the same for what you want no matter how you get it delivered...which makes the real decision about usability and reliability.