[CM30]

I think cleverness simplifies what are arguably two different but somewhat related factors here.

An interest in a market/subject that has the potential for growth, and the ability to execute on said interest.

The first one probably has at least a bit of a luck element to it. If your interest ties into a hyped up technology or field (like with crypto a few years ago or AI recently) then opportunities for wealth open up left and right, while if your interests relate to something society/capitalism doesn't value as much, then you're out of luck. At least unless you can force yourself to change interests/passions.

You also need good timing, though you could make a good argument for that aspect being luck, skill or both.