They own the mobile platforms because they blazed the trail as you put it.
That was the prize they were competing for, Meta was late with the HTC First / Facebook phone, and so they lost.
Of course they would have liked to own their own little mobile fiefdom, they are incredibly valuable platforms
Palm, Blackberry and Windows PocketPC blazed the trail. iOS and Android were relatively latecomers that arrived with a more competitive product (iOS because it was much better than the previous generation, and Android because it borrowed the ideas from iOS and was free.)
I honestly don't think there is a room for a third commercial mobile platform, after Apple started the smartphone market, and Google caught up soon enough after. Even strong and entrenched players like Palm, Nokia (with Tizen) and even BlackBerry could not hold.
In 2007, Facebook was way, way less mighty, and by 2012, it was late.
Speaking of Windows Phone: it had great hardware and good, innovative software. It's Microsoft's bureaucratic ineptitude that killed it, not its (possible lack of) merit.
Windows Mobile was more advanced compared to the initial iPhone in almost every way (to be fair it wasn't a particularly useful device on launch). Of course the whole is more than just a sum of it's parts.
> Even strong and entrenched players like Palm, Nokia (with Tizen) and even BlackBerry could not hold.
What do you mean Nokia with Tizen? Tizen was Samsung's attempt at continuing with Linux after Nokia abandoned MeeGo.
Nokia was the massive smartphone market leader with Symbian, but was a hardware company at heart and couldn't keep up with Android which ate its lunch by giving all the competitors a free, competitive operating system.
Before Android came along the competition didn't really have much choice as they were even worse at software than Nokia was. Who knows, without Android the landscape might still today be Nokia & Apple sharing the market -- or maybe Windows Phone would've managed to become the second system.
Was it really Microsoft that killed Windows phone? Or was it simply just too late. By the time it was really available I'm not sure there was actually a chance for a third platform to survive.
They were too early, and then too late. CE and Mobile just never had devices with enough processing power or good enough hardware UI to make them viable and enticing for developers.
In retrospect, after understanding more about tech history, I suspect the leadership of Steve Ballmer during the vital period in the late 2000s and Bill Gates' spending less time on Microsoft probably had something to do with this as well.
According to reported stories, Bill used to be really good at understanding how to squeeze the last drop of performance from slow hardware, a vital skill to have in the 1980s, yet subsequently became less important when desktops became fast enough. If they had Bill Gates leading the technical direction of the mobile OSes, the extra focus on speed optimization might have been what would have allowed Microsoft to do better during the smartphone wars.
Their versioning seemed like a big problem and caused a loss of faith in the platform. They had an incompatible version jump and then another odd thing going on around the next version.
Not sure if you were using Facebook in 2012/2013 but their implementation was horrendous. Everyone bemoaned its lack of true mobile first design while other apps were responsive and sleek.