You’re subtly implying that this smart person also has the resume to be allowed to be interviewed in the first place. (A common bias of thought by people working in tech, from my experience).

There are people out there whose problem is not that they aren’t smart, but that they don’t have the resume that is aligned with HR filters. Their two biggest and relatively substantial hurdles are: 1) not getting a chance for even a first interview because they are immediately being rejected purely based on their resume, and 2) having a weak position going into salary negotiations.

So, imho “a smart person can always get a well paying job” is a gross oversimplification often made by people who are not in such circumstances.