> There is a product development strategy (I'm not sure if there's a formal name for it) where you're given a lead on a finite-but-large supply of parts you can acquire for absurdly cheap; so you buy the batch;

This is how Aldi and Lidl fueled their growth. Instead of focusing on thousands of different product offerings, they looked at a narrower selection of products (~20 times smaller than their higher end competition) they can buy in very high volumes at substantial discounts. Their offering is defined by what is available for them at the time to buy under those conditions. Instead of ensuring a specific product is always available on the shelves, they might just stock a different product at specific times.

This is less obvious when 90% of their sales are under their private label but the supply behind it is whatever they can negotiate for a better deal.

Their "middle aisle" is the perfect example of this, it really just stocks a mix of whatever is the cheap product of the week and may no longer be available next week at the same price so they stock something else.