Most consumers just don’t want the hIgh HDD capacity any more.
Picking a random shop (John Lewis ;) , they have 154 laptops.
The middle of the market is 256-512 GB, and tops out at 1TB. I’m preparing for a bunch of downvotes from people saying “yeah, but How Can I Do My Video Editing / Proper Work”. To which the correct answer is “YMMV, there are a few of you, but most of everyone else just doesn’t do that so much”.
Point is, if most people decide that 512 GB is enough for them, the cost differential between SSD and HDD just isn’t enough to worry about. Ditto for desktop at x2 capacity