I think there's plenty of developers that are perfectly competent with CSS who still reach for Tailwind.

You're right that Tailwind throws away the cascade, or at least enables developers not to have to think about it (under the hood, Tailwind 4 uses pretty modern cascading features like layers), but people aren't reaching it because of a lack of understanding, they're reaching for it because as front-ends get increasingly componentized, the cascade becomes less and less of a benefit and more of an obstacle to be worked around, and something that gets that obstacle out of the way becomes more attractive.