Several movie and TV sites have come and go where you can just visit and watch without even creating an account. Quality might not be as good as a paid service and they are no doubt in the grey-to-red zone legally. I don’t see the same service for music.
Why do you think is there such a difference in trends?
The payout for audio ads is a lot less than video advertising. It’s just not as profitable to do an entirely ad-supported music streaming service as a video one