clearly this time it'll work out, considering that the store is part of windows!
although the windows phone OSs have had app stores built into them for years. they languished with poor support while microsoft built better apps for android and iOS than they did for their own platform, and now windows phone/mobile is basically a dead platform.
so again, maybe not.
You do realize the windows store has been there since windows 8.0, and has never been a success at all?
Microsoft thinks they can make a lot of money through their 'store' as Apple does too. But it's just one of the many streams of income they have, the same goes for gaming/xbox. Their core business is shifting towards Azure mainly (and other cloud services), and the 'store' is just a side way to make money off Windows client. Games belong in the category of 'apps' one in theory would like to buy from an 'app store' so they put games in their store, and every PM in Redmond is pleased. Whether it actually works out or makes money is a much more complicated story: it's similar to how the whole XBox project likely will never break even, even though they make money today. It's not their core business, not a pillar the company relies on, and if it fails, too bad.
For us gamers it's a bit of a problem if you want to play a particular game that's exclusive to their store but in general not that big, as it's not likely that many publishers will ever release their games in the Windows store and MS own portfolio is too small to make it the 'go to store for games'.
As app developers are not eager to write any UWP app at all, their store is a barren wasteland with only a couple of apps compared to what's available elsewhere. I don't see this change in the future, and IMHO I wouldn't worry that much: MS will be forced to either keep their games on Xbox One or publish them outside the store as normal software. Their plan would work if their games would have the pull they had in the early 360 days, but nowadays it's more a matter of 'oh, an MS game, can't play it, too bad, let's play something else', and therefore their 'exclusiveness' hurts them only, it doesn't create what they hope it will: a successful store.
Microsoft itself is also to blame for this btw: they first alienated the developer community with their WinRT initiative (the OS API), and the divide between DevDiv and WinDiv, then came with a new platform again after WinRT, UWP, and with the failing phone OS, there's little incentive to go UWP over what is already there (win32/.NET/WPF). With the upcoming \\build conference we'll likely will see more success stories how great UWP is and a lot of noise, but at the end of the day one has to conclude: it has failed, and the long term options for MS are: clients: iOS/android, server: azure.