(I am a bit surprised they didn't bung Google and StudioCanal a bit of money to move them to Google Play to avoid the bad publicity though.)
It's typical "you own nothing" logic to the point the companies selling you that also don't even own it.
- Disney -> Disney+/Hulu
- Universal/NBC -> Peacock
- Warner Bros. -> Max
- Lionsgate -> Lionsgate+
- Sony Pictures -> The Sony services relevant to the article (note: the Sony services sell more than just Sony Pictures content)
They never needed to, but it actually makes them more money because a revenue share model through Movies Anywhere makes sense. StudioCanal does not sell streaming/delivery services directly to consumers, a revenue share model between streaming providers would not make them more money, and Sony would have no influence on StudioCanal doing so anyways.