How Much Strategy?

I'm working with a group of directors who are responsible for an area that is tactically focused.
We've been gathering to determine a long-term vision for the team, and they are feeling some frustration during the process.
Now, most vision exercises are frustrating - if not, then you're probably not challenging yourself enough - but this one seems more painful than usual.

Every time we start to break through to a strategic discussion, it seems we can't stay there for more than 15 minutes before one of the members is compelled to dive back into a specific tactical point.
Last week, we discussed the fact that thinking strategically is like a muscle, if you don't use it, it atrophies. One member then suggested working on this for the next 6-9 weeks and you could see rolled eyes and hear some groans.

This prompted a question from me - how many hours a week should a director spend on strategic thinking? 2 hours a week would mark less than 5% of their time (I don't know any Director level employee who puts in less than 40 hours/week - certainly not these guys).

So, is 5% too much? Not enough?

How much time should a director spend?
A manager?
A VP?
A GM?
Who owns strategic thinking? And why is it so hard for most people?

Tell me what you think...