No it's absolutely not close to correct that most mainstream computer systems don't have upgradeable RAM as stated in this article. Source: I have an IT company

No it's absolutely not close to correct that most mainstream computer systems don't have upgradeable RAM as stated in this article. Source: I have an IT company. I can see that saving a mm or two with this form factor would be advantageous though. Slots change every few years anyway - DDR3, DDR4, DDR5 all have physically incompatible slots so moving to this new saystem isn't that big a logical change.