This is pretty much assured -- particularly with Disney.
We just heard about The Orville moving to Hulu and I can remember getting Netflix to keep up with Longmire. These services are getting too expensive to jump for one or two shows.
I see it as a glass half-full situation: the streaming services are
saving many good network and cable shows from permanent cancellation. That was certainly the case with Longmire, The Expanse, The Killing, Arrested Development, Lucifer, and a few others. With Orville, Seth McFarlane wouldn't have been able to deliver a season 3 in time for the network schedule, so Hulu provided a more flexible platform to allow the show to continue, as explained in this
Variety article. Hulu is also rebooting Veronica Mars.
Speaking of flexibility, streaming services also save shows in the sense of allowing for varying episode run times and removing a lot of the network content restrictions, allowing the show's creators freer rein in realizing their original vision. Not to mention, in general, the video and audio quality on streaming can be a big improvement over the bandwidth-starved, over-compressed quality of many cable TV providers. We'll certainly see new episodes of The Expanse in 4K long before we would've ever seen it on Syfy via our local cable provider.