A crisper statement of your "outlier" objection is "selection effects." Well, yeah, the reason many Wall-Street types are rich is selection effects (though lately much of the wealth of the politically-connected ones seem to derive from feeding at the public trough). But Buffet has made so many public bets and profited so much from them that selection effects might turn out to be quite unlikely an explanation if you did the calculation.

Remember: the more bets a bettor makes and the more profitable a bet turns out, the less likely the whole series of bets is the result of luck. It might be the case that the probability of the "Buffet just lucky" hypothesis is so low that you would not expect to see even a single professional investor with Buffet's track record (or a better track record) even though there are 100s of 1000s or millions of professional investors if the professional investors were just rolling the dice. Eliezer's "Einstein's Arrogance" (its the first google hit) is a good explanation of this point though it takes a little work to see how "Einstein's Arrogance" applies to the present topic.

Selection effects is the most likely explanation I know of for why most rich small-business owners are rich, which makes it odd or perverse for you to hold up the small business owner as an alternative role model. (In the U.S., unlike the avg founder of a tech startup, the avg small-business owner earns less than the avg employee. Smal-business owners, like investors, though, have more opportunities for dice-rolling than employees do.) In other words, I think you have it backwards.

This is not to say that there are not small-business-owning strategies (even ones that do not involve tech development) that can do much, much better than rolling the dice -- just that most rich small-business owners probably did not follow those strategies.