Maybe this has been posted before, but I'm convinced it's a power thing. Companies make such a big deal about résumé gaps because they're afraid they won't be able to hold as much power over someone who is willing to up and walk away at any moment—or who doesn't make constantly working part of their identity.
My dad was absolutely over his job for at least a few years, just dreaming of retirement, holding out for the slightly better pension. Then he died of cancer at 61. If I have the means or opportunity to take multiple mini-retirements while I'm still young, you can bet I'll take them.