In the corporate world, it’s common for top executives to be recruited from outside the firm, even outside the industry.  But in American politics, convention and sometimes law require politicians to have longstanding ties to the geographic areas they ostensibly serve.  

That shrinks the market for politicians: If a governor has apparently done a good job running a small state, why not bring her in to run a bigger state?  Why shouldn’t Americans be able to at least consider Tony Blair or (after his term ends) Manmohan Singh for President?  
It’s not like it hasn’t happened before.  In the late 1600’s, the British had the right idea: Look around the world, find the biggest economic powerhouse, and import their CEO.  
You can see why the Dutch stadtholder William of Orange (half of the future William and Mary) was so appealing: The Netherlands was The First Modern Economy in the words of de Vries and van der Woude.  Plus William looked good on a horse:
The history books usually talk about the religious disputes that led to William of Orange’s rise to the British throne, but economic motives–or at the very least, national status hierarchies–had to be in play as well.  When you don’t know where success comes from–when the production function is a mystery–you might as well copy the market leader’s every detail (if the opportunity cost isn’t too high).  
Yes, you can go too far, one of the many points Spike Lee was likely making in this excellent commercial.  But CEOs matter, so you should at least consider an external hire.  In American politics, we don’t do that. 
Most of the barriers to political imports seem cultural: To many voters, it just seems weird to have a mayor from Albuquerque run for mayor of Seattle.  But nobody blinks if the CFO of mid-size bank becomes CEO of a larger one.  In other words, here, as in so many cases, we should blame voters for democratic failure.  
From the comments: Hadur notes that the Poles and Hungarians often imported their kings (wiser to shop around when the local sourcing market is small), and Thacker notes that Sam Houston was governor of Texas and Tennessee.  
Houston is still the only person to serve as governor of two U.S. states.  The absence of gubernatorial recycling is prima facie a failure of U.S. political markets.