[curtisf]

What is the actual model that takes 15 seconds to compute?

If I understand the setting, you are estimating the demand curve for a given price... And there are only 40 such curves to compute.

Surely each curve is fit with only a few parameters, probably fewer than five. (I think for small price ranges the demand curve is usually approximated as something trivial like y=mx+b or y=a/(x+b)+c)

Why does evaluating the model at a particular price need to take milliseconds, yet alone 15 seconds?

[kookamamie]

This is the right question. The article reads like answering a XY-problem, where instead focusing on the actual issue, the author triples down on polishing a turd.