You're getting at intuiting requirements, which I think of as a mid-level or senior dev skill. Super important for orgs without massive product/design resources, but it's different from this garage test.

I can certainly believe a good number of programmers couldn't, for example, figure out how to build a database on their own, or a 3D game, work with cryptocurrencies, or reverse-engineer an API. There's a reason FizzBuzz is still a valuable gating test.