As an example of a loophole, investors can buy stock in a company, hold it for five years, and currently get 0% capital gains on the appreciation.
You don't need an intermediary to do this; you can do this right now.
It's just that most regular people don't have the money to invest, and if there's no money to invest then there's no money to apply toward loopholes.
And then you have to pick winners.
Same thing with putting company investments in Roth IRAs. This tax loophole would be idiotic for any normal person, but with somebody who's not planning on using the Roth for retirement it makes perfect sense.
But, you have to pick winners or Joe sixpack just lost his retirement savings.