The evidence is the published research of the psychometricians (who also provided the evidence for IQ that you are quoting). IQ certainly has a far longer track record, but that proves nothing. But this isn't my area of science, so I don't know the full extent of their basis.
A single publication versus hundreds just doesn’t get it with me. I am a bio scientist, and trust me, there is a lot of misinformation that gets published. The long track record with experiments replicated in multiple labs is what establishes the truth that withstands the test of time. I have seen too many publications retracted and withdrawn. I’ve also been on selection committees that select who is qualified to enter the professional school and who is not. Admittedly, most of this committee work was back in the day when students gained entrance based on merit and not race and gender where applicants have found a new way to cheat by excluding the more qualified applicant.