So I'm 20 and I've started looking at the salaries of jobs/careers, and this is the impression I've gotten. Like that you could spend years cramming a ton of knowledge about a very niche field, and still only get 2-3x what a run-of-the-mill job makes. Is this true? If yes then I guess this route to wealth would only make sense (due to the diminishing returns) if the topic truly spoke to you, right? Are there alternative career paths to good pay than being really good at something really specific?
OP, I gave a funny sort of answer to the question itself, but it occurs to me that I should address your text separately. If you have options, you absolutely should pursue something you feel a bit of passion for, unless your passions are all hella impractical. The sweet spot is something that allows you to not worry about money, and that you don't completely hate or even low-key enjoy. Hell jobs that earn a bit extra and being a starving artist that will break in any time now, I swear both get shit reviews (unless done on cocaine).
At 20, something I didn't realise is that you're not supposed to "get rich". I feel like culture sells the idea that we're all supposed to be Steve Jobs or Elon Musk or something. That's bullshit, even those guys aren't what they claim to be, and the messaging about striving for it is basically propaganda to make people like them feel better. I don't care how smart and amazing you are; real adult life, at it's best, is about earning x dollars, and spending exactly x dollars on a mix of things today and on investments so you can retire down the road.
Also, you said big jobs "only" make 3x a normal job amount, but where I am in life just an extra 10% a month is basically the difference between two very different situations. 3x someone else's salary would make the world your oyster. (Although, most people with money get caught in lifestyle creep and never consider what they actually want)
Another thing my teachers explained to me, but not very well, is that it's hard to know what you enjoy doing up front. Expect to change courses, not because it's helpful (it's rarely so), but because you basically have to as you gradually get the hang of things.
Hazardous jobs, shift work, really unpleasant (even evil) jobs. Education still blows them out of the water, though. IIRC most degree holders eventually earn more than an underwater welder or ice road trucker. Other than that, there is no free lunch. The only way to make money for nothing involves having a much larger sum of money to put in up front.
Edit: Oh, I should also mention the college brochures are full of lies. Most people probably know that, but I was dumb enough to take them sort of seriously. A thousand words of that stuff is worth a couple of sentences water cooler talk on a website like this.