You know that these things are ever evolving. In the 1980's you could change all sorts of chips and boards in a PC. The Controllers were separate. ben now the system architectures are head towards Systems on a chip resulting in much fast systems that will last longer, but ironically will become obsolete anyway.
It wasn't long ago that WiFI, Bluetooth, Sound, Hard drive controllers, Ethernet were all removable and now they soldered to the motherboard.
It's partly down to efficiency. It's very true that to achieve the best Speeds, Interconnects should be removed. DIMMs do slow things down and can cause problems. Most of the time when a DIMM fails it's due to heat generated at the gold connectors burning out.
I do agree it's a shame they are not expandable, but the way I see it I have the first macbook air 2008 and still runs like new still with 4gb ram and I've just installed Yosemite and it's fine.
The most Ram Hungry App I know is After effects and with 16gb in a mini you have 4gb per virtual Proc which is way more that the recommend 2gb.
Sure, but all of those parts are still removable on most high end systems.
If the argument was about consumer systems becoming more integrated sure, that makes sense and that's where things have been heading since the 1990s with the iMac Bondi Blue.
But the original statement was that NO system was going to have removable parts, which is gibberish. The cloud computing that we rely on more than we do our RAM allotment runs on 24/7 running machines that have hot swappable parts all the way up to the mobo. These infrastructures won't tolerate the idea of turning off a machine and throwing it in the trash.
Then you have the mid tier systems used in many content creation sectors that also need the 24/7 reliability found in systems that can remain running while a HDD, RAM, Mobo, Ethernet, etc is removed for repair or integration. Those systems usually need multiple configurations and PCI cards hooked into different pieces of hardware for redundancy and connectivity. Avid ISIS based systems need faster NIC cards that are compatible with Avid hardware and maybe even FIBRE channel that's preferably NOT external and taking up valuable rack space.
In the end, it's okay to assume that the future of computing is going to based in novelty systems . . . .that's fine and has been talked about for longer than most users on these forums have been alive.
But to say that everyone in every industry across the board should be fine with 16GBs of RAM total is absurb.
Lastly, even After Effects is a mid tier piece of software. Running it alone might only require up to 4GB of RAM on the Mac, but on PC based systems it can use up to 8GBs and that's normal for some deeply layered comps.
Then there's software like Avid Media Composer which uses more system resources than most can imagine. It's wicked fast, and even faster when running the ISIS clients and connecting over networked shared storage and some of the freelancers I work with have MC running along with After Effects, Photoshop, and maybe a Sorenson Squeeze encode running, all of which are RAM heavy apps.
Again, that's not to say that the Mini would be used in that environment, just that soldered RAM is perfect for consumer systems, but it's not the best solution for all systems across all industries.