I actually believe Apple works with Best Buy and Amazon and perhaps some other retailers to dump inventory. I mean I don’t think Best Buy is going to lose $250 - $300 off a 15” MBA that Apple is eliminating next month since they will introduce the M3 version. So Apple doesn’t want to show it ever discounts, and I know some people who only buy at Apple Stores, so Apple uses third party retailers to dump the inventory that will be outdated soon. I also believe this is how can get $2k off an M1 Max MBP at Adorama or B&H!
It’s obvious Apple bought more than they needed of all of these from their suppliers, or to use the components and get proper economies of scale they just kept building beyond demand. One thing I know for sure is AAPL is still making plenty and the third parties are making money on them too!