I've never run into someone who that is their career - do you work for companies that are trying to take the competitions stuff apart, or legacy hardware, or is there some other stuff that's obvious that I'm missing?
Think more along the lines of "bad guys" vs "good guys" rather than corporate competition. Perfectly harmless systems are built everyday. But, the consumers of those systems may not always be harmless. Understanding - and eventually controlling - the inner workings of these custom systems [covertly in some circumstances] is often necessary to stop the bad guys.