Why doesn't every investment property in California have an ADU?

[Brian Bakerman]

Adding an ADU to a property has become super easy in CA, yet it seems that the adoption rate of adding units isn't quite where it could be.

This is most surprising amongst investment property owners. Why is that? The math makes a TON of sense, units can be installed in as little as 2-4 weeks to coincide with tenant turnovers, home equity seems to be at an all-time high -- what's missing in the equation?