It's a "shortage" in the normal colloquial use of the term because the quantity of housing demanded exceeds the quantity supplied relative to some spectrum of desired prices. "There's no shortage if you have $2 million!" is hardly reassuring. I think you're misapplying the jargon found in economics textbooks. On that definition, the recent spike in rice prices which will lead to millions of people starving is not a "shortage" because prices were allowed to rise. Sure, but that's silly. What people normally mean by "rice shortage" is "there's not enough rice". It's not enough precisely because prices are too high.

If you like, call it a "supply-demand imbalance" or an "affordability crisis", but it doesn't change anything. The point is, supply is so low that it's causing a lot of human misery. In normal English, that's called a "shortage", because there's not enough of it.