Both are either introducing or toying with the idea of introducing ads. Because paid + ads still makes them more money than just a regular subscription.
And since the goal is to make always more money the future is gonna be paid subs + ads.
I don’t really think this is gonna fly. It’s quite jarring having ads before or during a movie (even at cinemas, but at least it’s once in a while). With cable you could switch channels, but streaming is a more personal experience. Especially when you’re supposed to have control over the programming.