Not really. My thesis is that IF the stock market is NOT a casino, then the capital gains are real income, thus they need to be taxed. For example if the stock prices were set by the companies and they were obligated to buy back shares at that price if asked, then indeed you have a valuable asset on hand. If the company increases the asking / paying price for the stock then you have real tangible income that you can realize. Similar to the interest you accrue from savings.

But if we agree it is a casino, then we should not tax air, only the ones who cash their earnings and walk out of the casino. And goes without saying that we should stop incentivizing people to gamble their money and pensions on this. 401k, Roth and all these need to go.