In my experience while I worked there (on Visual Studio and Chakra) it felt like all the major bad decisions were being made at the upper-levels of management - things like the original Windows 8 sandboxed XAML "Apps", the Surface RT, killing VB6 without giving users a clear exit strategy, the decision not to market Zune internationally, making Windows XP look like a toddler's Fischer-Price toy, or the Terri Schiavo-like treatment of Windows Phone - but conversely it's also where good decisions come from (Bash on Windows, Docker support, SQL Server for Linux).

Contrary to your point: none of the shareholders had any input on those decisions above (except possibly getting rid of Ballmer post-Nokia...). It's just management playing dice with ideas seemingly without much critical thinking - or at least transparency as to why they decided to press-ahead with a controversial decision.