Product Management, in many orgs, is the old wine of Taylorism in a new bottle, where there is a "thinking class," and there is a separate "doing class." The stereotype of an engineer with poor social skills who can't grasp the "high-level cross functional relationships and strategies" (from nostrebored's sibling comment) is not very different from Taylor's idea of workers:

    One of the very first requirements for a man who is fit 
    to handle pig iron as a regular occupation is that he 
    shall be so stupid and so phlegmatic that he more 
    nearly resembles in his mental make-up the ox than 
    any other type. The man who is mentally alert and 
    intelligent is for this very reason entirely unsuited to 
    what would, for him, be the grinding monotony of work 
    of this character. 

It is sad to see this happen at places like Google, where engineers had a lot more autonomy.

Most knowledge workers who have the mental capacity to grasp deep technical topics will find the "cross functional relationships and strategies" discussed in garden variety business books a light stroll in the park.