I'd add shorting is expensive (borrowing fees or volatility premium on options) ...

sf_rob on Jan 22, 2020 | parent | context | favorite | on: Tesla races past $100B in market valuation

I'd add shorting is expensive (borrowing fees or volatility premium on options) and more complex (margin/option approval etc). Plus the old adage that the market can remain irrational longer than you can remain solvent.