On its own it isn't good. But I asked my Japanese boss one time why people in Japan mostly stick with one company. He said it's pretty much just that the company one is with is almost invariably always the one that will pay them the most money. Also job security. Once you've been there a few years you'd almost have to try to get let go.

Kind of obvious shit but it was interesting hearing it right from the horse's mouth. In America, if you are a good worker you can generally find someone willing to pay you enough to job hop every couple years if you wanted. Japan not so much, but I wonder if that will become more prevalent as population decline continues and companies are more desperate for people.