According to Duann, PC makers have to buy from SSD module makers because NAND vendors reduced allocation to the client/consumer PC market and redirected most NAND supply to data center products.
As a result, PC OEMs like Acer, Asus, Dell, and HP cannot get enough NAND or SSD supply directly from NAND manufacturers and have to turn to module makers for solid-state drives. The latter traditionally served end-users and had plenty of aftermarket products with enhanced performance and cooling, but now they increasingly serve PC makers instead.
My PC from 2019/2021 ist now still worth more than it was when I first bought it. Why the heck would I upgrade to someting worse for the same price? Or to something as good for a worse price?