Sure, for the most part.
What about productivity stuff (for instance) though? It would make just as much (if not more) sense for a new productivity app to take off on desktop/tablet as it does on an iPhone.
Look at the app store purchases Microsoft made last year (hurr hurr).
Acompli (Mail)
6 Wunderkinder (To-Do list)
Sunrise Atelier (Calendar)
Productivity apps that started or took off on the phone. None of them had iPad apps at launch. Of those, only Wunderlist has been on the Windows Store before the acquisition.
Productivity in general is huge on the iPhone. Search for "productivity apps" and check the "Top XX list" any shitty blog puts out. I bet you that more of them have a web app than a dedicated Windows app (Win32, Store, UWP).
But lets look at games. It's the biggest category on the Windows Store by far.
Then you look at Disney, one of the arguably biggest supporters of the Windows Store, and you see none of the latest Star Wars and Marvel games. I thought it would be cool to play some of their F2P Star Wars games on the PC, as a little time waster and I've heard that SW Galaxy of Heroes is actually pretty decent. It launched at the end of November 2015 and is nowhere to be seen on the Windows Store. I have no idea why, because Disney Crossy Road is new and on the Store. So that's not great.
And what a huge mess UWP has been for traditional Win32 games so far, is clear to everyone here (I hope).
e: Little fun fact: In the last Windows Store report in February 2016, Microsoft mentioned that the majority of the downloads from the Windows Store came from Windows 8.x. That was a month after they announced the 200 million Windows 10 users.
Windows 10 adoption trends
As announced in January, over 200 million PCs, tablets, and phones across the globe are now running Windows 10, making it the fastest growing version of Windows in history. Over 3 billion visits have been made to the Store since the Windows 10 launch. While Windows 8.x still accounts for the majority of Store downloads, Windows 10 users are the fastest growing download segment, growing both in volume and total percentage of downloads
This past holiday season we saw double the number of paid transactions for PC and tablet customers over the previous holiday season, and Windows 10 customer generate 4.5x more revenue per device when compared to Windows 8. For more information, please refer to the Windows 10 Store Growth opportunity post.