> Why is buying something 10x more powerful than you'd need at 2x the price "good value"?

So a MacBook Air is 2x the price of the very cheapest laptops. Trouble with the very cheapest laptops, though, is that they use the very cheapest chips; Intel is not making a lot of money on those (if they're Intel at all; these days a lot of that category is ARM Chromebooks). The MacBook Air's actual competition is more capable laptops in a broadly similar price range. These use more expensive, higher margin, usually Intel, chips, like the MBA did pre-M1. That has to be a concern for Intel.