Also allowing users to upgrade RAM themselves would lower Apples margin and their computers would remain usable for much longer which would result in even less

Also allowing users to upgrade RAM themselves would lower Apples margin and their computers would remain usable for much longer which would result in even less profits... Now Apple can release a 512 GB version in a year or two then a 1TB one etc. The technical issues are totally insignificant compared to this. Edit: having said this extra memory for Mac Pro seems cheap as f** by Apple standards. Just $800 for 64 -> 128GB. 8 -> 24GB for Mac mini/Air is $400 and you only get 48GB for $800 in a MBP.