The current “Tash Can” Mac Pro is not really upgradable. It has proprietary GPU and SSD interfaces and no other PCI slots.
You might be able to purchase a replacement SSD for someone like OWC or upgrade to the higher spec Apple sourced GPU if you bought a low end model but Apple is not expecting you to do this.
You can update the RAM or use external thunderbolt peripherals but that’s a long way from the older “cheese grater” Mac Pro.
If I was to guess I would say that this deliberate removal of upgrade path is actually about design for reliability.
If you remove the upgrades you remove the chance of static damage or use of faulty parts. Also the case is easier to manufacture and more robust because it’s less complex.
I think that’s the real reason the SSD is now soldered in the current MacBook Pro but it’s just a guess.
Re:The truth about Apple's engineering [video]
by 20after4 on Sunday April 29, 2018 @05:00AM
(#16951261)
If they didn't solder the SSD you could buy their smallest one and then drop in a huge SSD at 1/4 the price apple would charge for the upgraded storage. Apple systems are very expensive for the base model but where they REALLY tax you is anything with upgraded specs.
If you want upgradeable hardware then buy the Mac Pro since it was the model designed for that purpose. Otherwise you need to understand that upgradeability comes at the expense of thickness and weight since those clips/sockets take up valuable space. And people that want upgradeability simply aren't Apple's market. Go buy something else instead.