Thanks for the link. Yes, we should certainly consider alternative asset classes: Real Estate, Farmland, Options Trading, etc. It always pays to add uncorrelated and high-return asset classes. 

Would be nice if someone could find a way to bundle farmland investments into large diversified index funds. Right now, I'm hesitant to give money to Acretrader etc. because it's too much of a hassle to keep track of K-1s from each individual farmland investment. 

I'm wary of the various promoters going around offering supposedly counter-correlated asset classes wrapped up in a nice little package with a high expense ratio that will help us escape the Everything Bubble. This is the same market niche that cryptocurrencies and NFTs were invented to exploit. Now the people who bought crypto/NFTs on that rationale are finding that these asset classes are suddenly correlated with the stock market instead of counter-correlated, and suddenly they are riskier elements of the portfolio rather than the hedges!

Agricultural land is now being marketed the same way as art funds and crypto assets. But it's hard for me to understand how we investors can be sure the land is being managed well (e.g. crop rotation, irrigation infrastructure, fertilizer, etc.) or rented well (there are only a few adjacent farmers to any particular field). 

Look, if you want a counter-correlated asset that always performs exactly as expected - and which even publishes its delta, or degree of correlation/counter-correlation, then you are looking for a put option, not an AA full of weird stuff. You can buy literally years of counter-correlation with LEAPS options. Then you don't have to presume a relationship between farmland rents and the price of SPY.