I daresay that if libertarians were elected, in fifty years they would be as corrupt as the current crew. Well, we will have had fifty years of restored freedom, and having to fight the same battles again and again is the way of life.
To be libertarian by definition requires a base philosophical set of rules. Evaluated on the aforementioned total departures from platform (although such a term implies more stability than clearly deserved), if republicans had similar (any??) standards, George Bush, by definition, would no longer be republican.
Instead, and alas, Hoorah! for the Republican Team.
In any event, to use your own terms, even just 50 years of something libertarian is better than the near total abdication of professed ideology exhibited by republicans at the moment.