The real advantage gains reaped are in things like tax avoidance and asset protection. These are vehicles that tend to be available to the really rich and only really useful to the really rich.
"Everyone above a couple mil gets 10-15% annually and just doesn't talk about it"... please. Bull. Shit. Those who do talk about it all the time. Those who lose their shirts are the quiet ones.
There have certainly been times when nominal yield of 10-12% was the norm (before inflation/taxes). Those days are not these days. And these days earning the market (domestic or global) with minimal cost is available to literally anyone with a checking account and a smart phone (in the USA at least).