Genuine investments in companies, real estate, and other hard assets which actually produce cash flow rather than BTC whose value depends on the madness of crowds and the tweets of eccentric billionaires.

Investment portfolios exist. They also reduce the cost of loans, thus making it easier for companies to grow and speeding up innovation. In comparison, the only thing "investing" in cryptocurrency does, is encourage larger economies of scale for cryptocurrency (which, side note, has built in mechanisms to actively prevent it from becoming more efficient).

I don't know a single person who holds their money in 'cash'. They invest it in the market, real-estate, business development, etc.

I am one who holds cash. Not all, but not an insignificant portion either. I have a mixture of assets. Why not invest that cash? None of the investment opportunities that I see fit my risk profile. Example: I'm holding my stocks now, but I do not plan to buy more.

The average middle class (and below) person in any highly developed country has a mixture of assets, dominated by their house and cash savings in a bank. Most don't directly own financial assets -- stocks, bonds, etc. However, they are invested in a pension (national or private) that will certainly invest in financial assets.