it is not he producers who do it, it is a service that you sign up for. a thir party, that is providing the horsepower.
And that’s the problem - the horsepower. It’s going to be really expensive effectively buying not only the rendering hardware - which is essentially a top-spec gaming PC per simultaneous customer, but also the encoding hardware, and the bandwidth to transmit the pictures (although realistically I expect the bandwidth isn’t going to be too high as they’ll transmit at 29.97fps 720p most likely).
Successful games might have 10,000 simultaneous players - so that’s 10,000 top-spec gaming PCs. For one game. Ahahaa.
Cas 
hmm and also there will be some unavoidable and significant lag so it really will rule out the proper nice FPS games. I knows this coz I work in broadcast. Even playing back local files can incur a 100ms lag, and that’s before any rendering, encoding, transmission is done, and before any input lag, and before any client/server lag between the rendering machines and the server machines.
Cas
Ok, but somebody has to pay it.
Players have perfectly capable hardware in front of them, but they have to pay not only to you, but also to the platform provider. In the end, it’s simply yet another (high) cost, and every dollar spent by the player on the platform provider, is not in your pocket.
It’s also worth noticing that this is just another impending trough in the endless thin-client/fat-client cycle. It’s happened at least 3 times already in the last 30 years, and I expect this is just another pointless fad before everyone realises that fat-clients are the way to go again. Meh.
Cas
I disagree about cost completely ruling it out. There would be a high startup price but buying, maintaining and running high-end machines in bulk will be far cheaper then doing this indevidually. You can also share the resources between multiple users lowering the cost per user even further.