Of the three investment options you mention as being better than the stock market, private equity is out of reach for most investors and crypto is, if anything, riskier than stocks.

Only real estate is a worthy alternative, and even that is difficult for most, since it requires a combination of significant capital and higher risk due to leverage.

Personally, I max out my solo 401(k), and have some real estate investments too. I just don't see many other plausible alternatives out there.

However, I did move into a (for me) conservative stance in my 401(k), with about 20% cash and 10% floating rate. I also diversified much more than I usually do into international stocks.