I think the above quote is accounting for both constrained supply and reduced demand from rising prices. Vendors consolidate their product lines to remove redundant (ish) offerings due to reduced demand and the new difficulties in managing supply chains. I.e. a shirt may only come in 3 colors instead of 10, and it may be harder to get the popular color because vendors are less likely to keep a large stock in warehouses.

It doesn't violate market dynamics that I can see, though I'm far from an expert.