You act like $100k/year isn't still well above average. Hell it's above what SWEs make in any country that's not the USA.

But pertaining to this article, the key to tiny Japanese restaurants such as these snack bars is that their startup costs are extremely low, rents are low and since they're tiny, they don't need staff so they keep all the profit. Probably good enough to make an average living without too many worries.