That doesn't mean sorting by IQ is ignorant. It means that you shouldn't rely on it entirely. Hypothetically speaking, unless there is literature indicating that a population of high IQ individuals is more highly correlated with lack of stamina or motivation than the general population, sorting by IQ alone as a first pass would still provide you with plenty of candidates who have the motivation and stamina you're looking for.
I think there are credible arguments against using IQ for various sorts of job filters. But I don't think your argument is among them. If we're at the point where we're implicitly taking that an IQ can sort people by "how fast they learn something", the only reason not to sort for that (if that's what you're looking for), is if that quality is more correlated with something else you don't want. I'm not familiar with any research suggesting that high IQ individuals are more prone to stamina or motivation problems in a large population.
I think there are credible arguments against using IQ for various sorts of job filters. But I don't think your argument is among them. If we're at the point where we're implicitly taking that an IQ can sort people by "how fast they learn something", the only reason not to sort for that (if that's what you're looking for), is if that quality is more correlated with something else you don't want. I'm not familiar with any research suggesting that high IQ individuals are more prone to stamina or motivation problems in a large population.