There are quite a few places that pressure pushes on a manager. One is they want to keep what they view as a well paying job, and they may not have very much control or choice in doing that. A good tech can take his tools and walk to the next dealer, earning pretty much the same benefits and pay (that's what I call the "joy of being underpaid"), but that is not often an option for the manager.
It seems to me, most of the pressure the managers are under is from the idea that you/they have to make more money than the owner (imagines they) would with the same investment in the stock market, or any other investment.
Then, there is keeping customers happy, who may be spoiled rotten with great service for years (and so imagine they would get the same level of service some other company), or have learned that if they complain they may get a better bargain (so they complain about everything, even those things not real ("the chains are all oily", after a PM)
OF COURSE the better, more trustworthy the tech, the easier job the managers have. But having the proper skill set to manage those techs is every bit as important, it's just seems even more rare than good techs.
difference between a wise man and a fool?
fool does not know what he does not know.
wise-man knows what he does not know.
seems like it would be kind of more difficult to know if the tech is a good one or not, unless you knew how to do the job yourself, most major league coaches may not be major league players, but they did play the game.