I don't know, I'd sort of welcome it if it happened. Between savings, severance pay, and my small business I'd be in an excellent position to go full-time, and being laid off would alleviate any social reservations I have about quitting. (Both in the "I promised my bosses I would stay a while to justify their investment in me" and "Salarymen who quit are not likely to be salarymen again" senses.)
This I don't think is true anyway. It has always seemed to me like a socially manufactured platitude to keep people erring as much on the side of safety as they can possibly reach. For the average person, it might be a very reasonable default, which is why the platitude tends to stick.
Otherwise, I don't know if the social reservations are worth worrying so much about. It's hard to tell how much of this is people legitimately looking out for you, and how much is them preemptive prevention from having to envy you and what you did that they couldn't bring themselves to do.
I have a... quirky relationship to these social norms as a foreigner, but that is another topic altogether.