the intention of the post you quote is to use inventory to explain price. inventory is a function of a rate of supply in addition to price. at any given price, there’s a rate of sale, and inventory will grow at production or new offer rate minus that rate of sale. 1/

so it’s a dirty measure of something that can, potentially, non-tautologically, explain price, but that dirtiness makes it delightfully difficult to interpret! /fin