Honest, non-judgmental question: why?
I get the value of loyalty to people. That I can go on board with. I'll gladly work my ass off or suffer to support people or causes I believe in. However, companies deserve no such loyalty. A pile of other peoples' money that will gladly get rid of you on no notice, or make you answer to an idiot, for any reason or no reason at all, is not worth emotional attachment or loyalty. It's just a thing that you should use (to pay bills and advance your career) while there are common interests.
Working hard when it matters is important and a true test of someone's character, but an unconditional work ethic is not a virtue-- just pointless.