Land and stock tend to go up in value. But land also sometimes go to 0, just like stocks.
With the booming American car industry in the 50's and 60's, who would have thought that houses in Detroit could go from having a premium price in 1970 to be sold for $1 40 years later?
Who's to say SF isn't going to be next?
The rockefellers and other "Old Money Family's" have the three rules to building multi-generational wealth. Land, Art and Gold.
Even for detroit, land prices have only increased since the 80's[0] and over long time horizons, i'm sure will be back in line with other "Single peice land bets".
I believe there are large parts of Europe that would take centuries if not a millennium to reach the peak value it had during the Roman Empire (measured vs gold).
In general I agree, though. A portfolio is fine.
Most people tend to have most of their "savings" in a single property though.
As an example, what do you think this $2500 property cost when it was new? (Edit: make that 1965, since it's quite old.)
https://www.zillow.com/homedetails/3226-Columbus-St-Detroit-...