Long-term investment is rightly seen as something to be encouraged hence the lower tax rates. You can make the argument that the rate should be more like 0% since the money invested and risked was already taxed most likely...20% is a reasonable value for the market regulating infrastructure provided by gov't entities.
The middle class isn't taking advantage of low capital gains rates to earn more from their taxable brokerage accounts because they haven't even filled up their tax-advantaged accounts.
The simple truth is that wealth beyond the ~$10M level in the US pays essentially zero "income tax". It just doesn't happen, no one does it. Short term gains are only taxed for small investors who don't know any better.
"Entrepreneur Elon Musk announced on social networks that this year he will pay 11 billion dollars, thus becoming the largest taxpayer in the history of the USA."
From Google: "For the 2025 tax year, individual filers won't pay any capital gains tax if their total taxable income is $48,350 or less"
If you've got a smart phone and a credit card, you can buy stock. See robinhood.com
You're just saying "Well, that's the way the tax code works". I'm saying "The tax code sucks", and your point is non-responsive.
If you bought a house, and it goes up in value, that increase will be a capital gain taxed at capital gains rates.
"Let them eat cake" makes for extremely poor federal revenue policy.