Also, quite a few people say they need 32/64 Gb of RAM, multiple high resolution monitors, large disks, huge graphics cards, etc. I don’t see a phone-sized device ever driving that, as needs will grow with hardware speed ups.
As for the 'there is no money in that' argument I believe that there is plenty of money in various iDOCKS, accessories, doodads and similar.
Because of that, I don't buy this particular theory - the first of the big players that provides a workable and friction free product will surely have it worth their while.
Also, for that predominant customer houses the device for consuming entertainment, I would think Apple TV + HomePod is more friction-free than a desktop could be.
Televisions have larger screens and are placed in better locations inside the house for that role.