How about PE as a proxy for "incumbency?" That is to say, you're looking at companies who figured out a formula to "print money" then let themselves get complacent and fat, thereby becoming targets for PE. This would explain why they tend to be not so agile.

I just had an image of a cabal of attractive young women, somewhat resembling James Bond villainesses, but who are trained in business and economics, who seek out dalliances with PE firm executives in order to perform industrial espionage.