This is a good argument, but I think you’re basing it on a false assumption: one can maximize one’s circle of competence for maximum wealth.
If Buffett had had the option to become a savvy tech investor, don’t you think he’d have taken it?
He didn’t miss these gains, he chose not to meddle in something he didn’t understand, knowing he probably wouldn’t have picked the right stocks in that industry. Tech stocks in 2001 were much harder to figure out than now pointing to the FAANG ones and saying “of course he should’ve picked those.”
If you try to expand your circle to include whatever makes the most money, you’ll likely fail.
Better to stick to what you can actually understand and make as much money as you can in that arena. That also means not everyone can be a billionaire with this strategy, but that doesn’t make it the wrong one.
Does that make sense?