[Disclosure: Microsoft is a client of the author.]This month, Microsoft announced that they would end support for Windows 10 Mobile by year end.

Thus ends one of the most painful eras at Microsoft (and one that was likely instrumental to Steve Ballmer being asked to step down as CEO).I followed the Windows 10 Mobile debacle closely.

At the heart of the failure was the near-complete lack of understanding for a competitive process that defined Microsoft initial success in the 1980s & and then was institutionally forgotten & called &embrace, extend, extinguish.& This, coupled with an inability to fund or execute timely, showcased another endemic problem that defined Steve Ballmer term as CEO: an inability to fully assess the cost of success and instead setting spending by some other method.