People are getting pretty pissed off at the gradual ad creep on something they pay for (subscription or otherwise...). Companies in their duties to their shareholders will have to make decisions on whether the potential loss from pissed customers who leave is offset by the increased revenue from the people who just whine about the ad creep but continue paying with their subscriptions and eyeballs.

Also, it is not always up to the streaming company. Hulu has shows that are excluded from the "No Commercials" bit because of their licensing agreements. So if you want to watch those, you still get ads.[1]

[1]http://www.slashgear.com/hang-on-hulu-ad-free-still-has-ads-...