Netflix bought DVDs to ship out as rentals. Content providers had no say (first sale doctrine?).
Netflix then saw that streaming was going to eat the legacy physical-disc market and pivoted.
At this point, streaming was a new revenue stream. Most content provider money was still coming through cable/broadcast. So they said "Sure, we'll license you a bunch of stuff for cheap to do this thing we don't care about."
Streaming's growth led to it overtaking other revenue streams. At this point, content providers looked at the numbers and said "The main channel for eyeballs is getting our content for cheap. We should do something about that."
And then built their own streaming services, e.g. Hulu.
The biggest miss here seems to be by Google and Microsoft. Why, for the love of profit, didn't they say "Hmm, we have data centers, software expertise, and bandwidth... let's build a B2B streaming platform offering for content providers."