You are not understanding the other possibilities here.

The other possibility is that yes, it is true that it is not that hard to make it to this level of success, but the stats are still true, and it is simply that people don't do this, for other reasons.

There are a multitude of reasons, as for why someone might not join lucrative fields, even if it isn't that hard to do so.

For example, maybe they simply aren't aware of it, or they incorrectly think it would be difficult. Or maybe there a social reasons why people don't do it.

Or maybe, in order to achieve that level of success they would have to move, and I know that lots of people don't want to do move.

My sister-in-law's fiancé is doing it as a journeyman, and he's making very close to what I do as a mid-level SWE.

This is not a very useful statement without a ballpark figure. Mid level SWE salaries range from <100k to >300k depending on the company.