There's plenty of precedent for this. Amazon has said they'll be introducing ads on Prime Video, where everyone has already paid for the service. I've seen ads on other already-paid-for services too. The simple fact is that business people will always want more ads everywhere, no matter how much it degrades the customer experience, because extra revenue is easier to measure than customer disgust. In their personal lives they probably hate ads as much as we do, but a fatter paycheck can buy a lot of hypocrisy.