Oh Microsoft, you do love being difficult, don't you? There are some great games in your back catalog, but whether it's Games for Windows Live, or more recently the Windows Store, why do you always seem to want to force people down routes they don't want to play them? You're no different from EA or Ubisoft in that respect, but do you really want to emulate those companies?
Fortunately, it seems, Microsoft appears to have lamented in the case with Age of Empires: Definitive Edition. Where once it claimed that it wasn't possible to get the game on Steam because it was using Xbox Live as a backbone in order to facilitate wider play -- as if people really want to play a fast-paced RTS on a console -- and that it wasn't compatible with Steam, it's now apparently changed its tune. There's no guarantee it'll come to Steam, but Microsoft has said that it's a distinct possibility.
It won't happen straight away though, with Microsoft saying that "before selling on another storefront, we want to make sure customers have the best experience, and other storefronts need to fully support Windows 10 before we bring Age of Empires: Definitive Edition over."
Let's face it, if it wants to sell more than a handful of copies on PC, it needs to make that happen.
Discussed in an interview with PCGamer, the status of AOE:DE is much more 'definitive' now and suggests that we may get some other Microsoft games ported over to Steam in the future too. Titles like the somewhat disappointing Quantum Break (sans TV show) and Gears of War 4.
AOE:DE is slated for release at some point in 2018 and brings with it a resolution bump to 4K, as well as new networking infrastructure and other visual overhauls.