It def is both financialization and zoning. Restrictive zoning increases the value of housing hence line goes up.

The difference is that financialization is a symptom of the problem, not the cause of it. It is enabled by the imbalance between supply and demand caused by the zoning laws restricting the supply.

Rezoning is framed as increasing supply and affordability, instead of decreasing values of existing homes. When both will happen.

"Increasing affordability" and "decreasing value" are mathematically equivalent statements, so yeah. Obviously.

(In fact, that's why the problem is so hard to solve: NIMBY homeowners will claim to be all for "housing affordability" in theory, but in reality they absolutely hate it because they benefit from prices being high. Zoning that restricts density is a symptom of society being held hostage by the already-privileged, demanding ever more subsidies for themselves)