Every once in a while developers resurrect a petition calling on Microsoft to make VB6 open source. It hasn’t worked yet, but maybe someday!
As for fiascos, I can think of plenty beyond the Windows Phone. Other examples that come to mind include the supposed iPod-killer the Zune, the full Expression line of products (intended to compete with numerous Adobe products), Microsoft Bob (intended as a competitor to GeoWorks in the era of Windows 3.11), the Cairo OS update with the legendary WinFS file system that never saw the light of day, Windows Media Center PCs, the KIN phone, LightSwitch, a half-dozen different ways to migrate Access databases to the web, the Courier tablet — the graveyard is full! I haven’t even mentioned promising technologies that Microsoft pioneered and then failed to capitalize on, like WindowsCE (supplanted by Android) and Terraserver (abandoned before Google Maps even existed).
And yet, still we are here today with Microsoft thriving on the things it did get right, which is pretty remarkable.