yeah, but that one was neither designed as a social safety net, nor is it big enough to function as one. It's neat, but it's so small that it's basically apples and oranges.

That's one of the problems with practicality of such plans - the numbers are never "big enough".

People take into account today's income and capital gains revenues, and assume that they can safely increase those rates by a wide margin causing no change in underlying behavior.

In reality a top-income earner who made eight digits or above can safely take the next 2-3 years off without driving his family into the soup kitchen situation, and as far as capital gains goes, people become more cognizant of harvesting capital losses before they sell anything that appreciated in value (or simply sell a smaller chunk of their assets, if we're talking highly liquid investments).