I do not understand why you assume that project managers are not thinkers and have no vision. Are you considering Project Managers are simply mindless robots following a tracking sheet? That's very different from the project managers I have been working with. And project managers are, by definition, NEVER at the top, since they are at the working level managing upcoming projects.
The problem is rather the lack of performance metrics. In all the successful companies I have been in, there was a strong correlation between success and the ability to measure progress from month to month, from quarter to quarter and year to year. When such things are missing, then you are pretty much depending on the goodwill and expertise of all employees, and usually this fails sooner or later.
In someway I think we agree when you say "project managers, are, by definition, NEVER at the top"
What I am saying is, that when they do reach the top, and in many many organization they do, they use the same skill set that helped them become very good project managers to lead an organization, and manage the future of its products
And as you said, by definition this doesn't work
What I am also saying, which is very sad, many organization structure their performance evaluation process around favoring Project Managers and eventually pushing them to the top
The problem is rather the lack of performance metrics. In all the successful companies I have been in, there was a strong correlation between success and the ability to measure progress from month to month, from quarter to quarter and year to year. When such things are missing, then you are pretty much depending on the goodwill and expertise of all employees, and usually this fails sooner or later.