Secondly, in this context, the assumption is that not only does this generalized attribute exist in humanity and we can measure it, but this attribute causes success in $job. That's a further assumption that I'd call into question. Sure, plenty of people who do well on $test do well on $job, but those could easily be covariate or epiphenomenological relationships rather than causal ones.
I don't doubt that for some values of $test, there's some discriminatory power predicting the presence of success, especially in more monocultural environments (affluent, often-white, often-male, often-young startups, to caricature). But I do believe that this kind of test would suffer from strong false negatives as many kinds of people who would otherwise be excellent programmers (or whatever other $job) are rejected for not doing well on $test.
That's why I worry about anyone who puts real stock in these kinds of tests - it is (generally) indicative of a kind of science blind spot in the user. People are critical and skeptical of all kinds of other scientific claims, but psychological measures tend to get a pass.
I imagine the fact that a lot of us tend to score well on IQ tests has a lot to contribute here. When I found out how many standard deviations above the mean my IQ score represented, I was pretty excited about how awesome I was. When I realized that the test was probably baloney, I had to figure out more interesting ways to shore up my self-esteem. Personally: I bake bread and fish for compliments on the quality of my sourdough.
I learned, as an adult, that I had taken an IQ test while young and had scored in the 99.97th percentile. I think that I got that not everything benefits from what IQ tests measure. That said, I had already started seeing great success in a knowledge industry.
It is clear that you also have great linguistic intelligence. I don't think you could completely dissociate your IQ test results from that intelligence.
The fact that certain groups of people tend to test well (or, taken conversely, that there are so many reasons why otherwise "intelligent" people don't test well) just exacerbates this problem and I think the central claim is still reasonable: things like IQ tests aren't necessarily strong predictors of tech skills, are dangerously close to pseudoscientific when misapplied, and have enough other theoretical problems that they should probably not be utilized during a hiring process.
As to my own linguistic skills, I contend that a lifetime of reading as well as a MS (in computer science), a Ph.D (in cognitive science and education), and ten years afterwards in academics including a professorship has prepared me as a writer. Did I have some initial Potential that gave me a head start? Maybe. If nothing else, I had the head start of my general introvertedness and a love of both reading and geekiness. A short test that purports to measure a fixed potential somehow inherent in someone is going to be pretty flawed.
But my "I don't doubt" phrase was more along the lines of ceding a central point: there probably do exist certain inherent characteristics that vary between people and provide some kind of predilection or head start. I'm just not yet convinced that the scientific community has really identified them yet, or that they're really able to effectively measure them yet. Instead, we get proxies that have a very high false negative rate, especially among otherwise-marginalized groups.
Anyway, four paragraphs is probably enough here.