At first, cable TV had no ads because it was funded by subscriptions. Then most cable channels slowly started adding more and more ads
and demanding higher and higher rates from cable operators to carry their channels. Then the local channels started demanding rates from cable operators to carry their channels that are otherwise available for free over the air. Then eventually they even started showing ads at the movie theater before the movie you paid to see.
What is happening with streaming services adding ads was entirely predictable because the financial incentives of a company that adopts a subscription model are to add ads to the subscription once they think they can get away with it. If they already have ads, the incentive is to add more and more of them until there's pushback (i.e. the NFL has been cutting down on commercial breaks because they got long enough and frequent enough to become a common source of fan complaints when ironically the 2 minute warning was originally added to the rulebook in the early 70s to guarantee TV broadcasters at least one commercial break each half that wasn't because the clock ran out on a quarter).
This is why all of the people who want a subscription based model for online services that are currently free are hopelessly naive. If they get their way, things will get better for a few years and then will eventually end up right back where they are but worse because you'll have to pay for the privilege of watching ads.