They're supposed to use their software update roadmap to decide to change the low-end model for one that'll get updates for longer, before they produce the surplus of inventory you're claiming exists. So for example, in mid-2021 they decide that at that year's Apple Watch reveal the Series 3 is getting replaced by a reintroduction of the Series 4 so that it'll still be a supported product while it's for sale.What else are they supposed to do with the surplus of inventory? Throw it in the landfill?