Statistically people with higher IQ and more education earn more...but only statistically. People with above average IQ have an easier time learning complex things that are harder for normal people to learn, getting them jobs that pay more, because less people are capable of doing them. It's not really complex. Additionally, there are a few entrepreneurs that make quite a bit of money thanks to their intellect. They make inventions or some such. But they're rare. The Bill Gates and the Elon Musks are outliers. Far more intelligent people work normal jobs, earning normal livings, living normal lives. Perhaps with a bit more intelligent conversations over their after work beer.

I'm not sure if they're "underachieving" though. Are they capable of more? Yes. Most people are. Doesn't have much to do with IQ. It has to do with opportunities. If someone with a high enough IQ has enough drive and doesn't care about the consequences, they can probably earn enough money to do a startup and get quite wealthy. But it's a lot easier if you're already rich to just get richer. You don't even have to be that intelligent.

The guy you gave as an example isn't a moron. The fact that you think he is kinda shows that you perhaps don't know what even normal levels of stupidity are. It's alright, it's actually pretty easy to not realize how stupid normal people are. He is working on a lot of normie level stupidity as information though. All the shit out there days, it's pretty damn easy to fall into such holes.

The other guy isn't without his own mistakes.

They're both working on their own piles of data...the first perhaps not getting quite enough...and the second getting a very selective bit... We all have our own piles of data. Some of them come in the form of fancy CGI graphics and Hollywood science! That data can seriously effect how "intelligent" we seem.

But IQ only tests certain things. Some guy might be able to easily tell you that some mopes are moops but have no clue about Shakespeare or the meaning of "his plays". I personally have always had trouble doing that whole meaning behind stories crap. But, it's not like my teachers focused a lot on teaching me how to interpret such things before they just started asking me.

That's the thing with pattern recognition. There are different kinds of patterns and such, and people that are better at certain tasks, but even if you are the best, you have to actually be trained on how to do something, with a significant amount of data, and the right data. That's why some of these new AI's are so fucking good! They train on a massive pile of data. But they are only trained for certain things. We're still figuring out the code for general purpose AI. So, some AI could beat you in chess, but have no comprehension of language. Or, it could tell you who has cancer, but not be able to tell you how to treat a cut finger. Or it could even write an amazing play, but have no comprehension of anything about the story.

Oh, and you totally can train to raise your IQ. Or at least train to beat the tests.