[gottago]

It does seem there's a move away from the now traditional Netflix subscription model to an ad supported model. I feel this was somewhat inevitable as the number of streaming services increased. The Netflix sub model worked where they were the only, or one of the few, major players but the more content is spread out across multiple services people just aren't going to pay for several subscriptions. So after a period of sharp growth in streaming the market is only now going to get smaller for individual services as consumers pick one or two services, and they are likely to favour the cheaper, ad supported ones.

This is only part of it I think. The streamers are at a point where they have such a hold of the TV market that they can now tap into an incredibly lucrative advertising market that will probably in the long term end up bringing them more revenue than subscriptions alone. Netflix has stuttered a bit with moving people to the ad tier and even filling ad spaces but now they're ditching the basic ad-free tier, and adding more features like being able to use the ad tier on multiple screens, I expect their ad tier will become dominant soon enough. 

Getting subscribers to pay you to watch advertising is basically a win-win for the streamers, as long as the content remains strong enough to keep people subscribing. Not unlike Sky, especially when it was at its peak and people didn't seem to care that their channels were full of ads.