"Only someone smart--and therefore expensive--can manage Linux security."
There in lies the problem with your argument. Whilst there are many self-taught administrators out there the comparable quality for a certified microsoft trained support person is vast and in the end whether your MS certified or have a RH or Debian Badge you should be paying much the same regardless on an hourly basis. Both can be remote updated, and both can be auto update. Pretty much cancels out the support costs see more more argument and comes back to initial price....