Re: There's also the Fligt Simulator franchise shutdown, and the utterly "Flight" failure...
Lockheed Martin still makes money from it (they licensed it) as Prepar3D, selling it as virtual training facility wher eyou can control the scenario fully. As more and more complex drones are available, it makes even more sense.
If you believe there are just a few dozen nuts, you're like Ballmer and have the same market sensibility. You may wonder it is actually used by real pilots and ATC controllers as well to train themselves (up it was used to test new real procedures in the simulated environment), and there are a good number of software houses making money selling add-ons, even for a ten years old product still widely used. It wasn't billions, but it was an iconic product, and the oldest one then still made by Microsoft.
But what was more interesting, it's not only the shutdown of the PC game studios (believing probably that XBox would have taken the world...), but also the total lack of proper product managment. Had they closed simply a product line with little or no revenues, ok, that's business. But they didn't. They believed they could "reboot" it following the fashion and believing to extract more money from customers with the "walled garden" approach.
They took a product manager known only for the "Ants" game (or something alike), put him in charge of a product he didn't understand, trying to turn it into something appealing to console users, decided to kill a long product heritage and its large 3rd parties support to impose a "freemium" model (fully controlled by MS) about which many warned MS it couldn't work for that market sector - they stubbornly went on accusing critics of being simply "whiners" - then after eight months the new product was shutdown wholly because only a few liked it, no money were made, but of course it wasn't because it was a bad product noone wanted really, it was just because of the "bad press".
Can you see a pattern here? It happened more or less in the Windows 8 years - an indication that within MS there was a culture shift leading to some key people being able to force their own personal views despite many signals - inside and outside - they were very wrong. How many billions allowing this kind of culture inside MS costed? And it's not getting better under Nadella...