> increasing supply isn't going to solve our many problems leading to widespread homelessness and financial insecurity

Why not?

(I guess I'm a "dunce", but I'm one that's ready for that conversation)

Being charitable here (though... when called a "dunce" it's hard sometimes to want to be charitable), the statement would be perfectly correct if slightly reworded to:

"increasing supply isn't going to solve many of our problems leading to widespread homelessness and financial insecurity"

It would just help with some of them.

But that's a statement that's obvious on the face of it - cheaper housing costs buy time if you lose your job, and makes it easier to have a bigger emergency fund, but it isn't an infinite reprieve. So. The charitable interpretation still hits a wall because that would be acknowledging that supply would help with some of them, and the "dunces" nonsense suggest that they wouldn't agree even with that.

(In some states in particular, though, home ownership is uniquely protected in ways that would help fight homelessness, so increasing supply and incentivizing selling-to-an-owner vs being a landlord could be very helpful too.)

Abundance only solves scarcity if scarcity is the problem, but the actual problem is economic exclusion, which will always be able to outpace abundance because abundance has physical limits while exclusion does not.