There other costs though. Some of these costs could set back conpetition since MS own a large amount of servers that others will have to rent.Maybe, maybe not. The economics of consoles are in licensing fees paid by publishers for their games to be available on your system. This is a literal licence to print money for the manufacturer so it's really about ecosystem lock-in with hardware being the mechanism to date. But hardware is a double-edged sword, while you profit wildly on peripherals there are many costs sunk into console development and while the goal is sell all hardware at a profit there's no always possible initially so you're carrying R&D, manufacturer, shipping and marketing costs before a single game has been sold. Equally, customers having to buy a fairly expensive piece of equipment is a significant barrier to entry.
Now imagine replacing the hardware cost barrier with a BYOD approach, like Netflix. Or PlayStation Now, and whatever it is Microsoft keep hinting at. You need a controller, but that's it - and the controller is a high-profit item.
Sounds like a winner to me.
Maintaining servers for such a service is a cost. Maintaining hardware per customer that render the games and stream them is additional cost. Although I suspect that could benefit from economies of scale of some sorts. On the other hand a hardware sold is a one off cost. If you are Sony and Nintendo you have all these costs plus the cost of renting. I dont think these companies can sustain competition in a market that replaces consoles with streaming services. MS has a huge competitive advantage that very few will have thecresources to match.
I am alsi unsure if this will ultimately benefit the consumer or not