The modern welfare state (post-1930) did create a huge number of these stunted people. UBI will create many more, and it'll be a generational compounding effect, as the stunting increases through generations and we develop familities where no ancestor has worked for 3+ generations.

Just reflect for a moment on how many of such stunted people existed in 1925, compared to today. Now apply that difference again a few more times, to a segment of the population with above-average fertility, and guess how many generations such a system can last.