What is really disappoint is how ignorant people are with respect to technology.
First; many of Intels Mobile chips can only address 16GB of RAM. If you order a Mac, using such chips, with 16 GB of RAM there is no possible upgrade path.
Second; the industry is moving to faster and faster RAM interfaces and in Apples case very low power RAM in the new Minis. This requires soldered on RAM. Here is a brief explanation of some of the more common features of LPDDR3:
http://www.virtium.com/blog/ddr3l-vs-lpddr3/
Third; soldered in RAM is only a stepping stone to RAM built into the processor module. See Knights Landing info for where Intel is going here. This of course is a Xeon Phi but workstation tech eventually works it's way down into the desktop. Why would they do this? Performance actually RAM is a huge bottle neck for today's processors and to go faster you need very fast and short buses to the CPU chip.
Fourth; what is all of your whining about hard drives? Hard drives are still upgradable in all Macs. Further the external storage solutions available these days are not excessive slow. Storage just isn't the problem it use to be.