What do you mean widespread uptake? What software doesn't run on either? iOS has the largest app store and best apps by a country mile while OSX runs everything that matters and is the preferred dev machine (at least for OSS devs) due to its Unix roots.
"Apple is using almost completely generic PC hardware at this point. See my other post regarding hardware."
It is way way way easier to optimize a few specific pieces of hardware working together than trying to support all of them. It becomes a worse experience for end users and a distraction for the company. The mobile space is the most stark example of this. (where the hardware is also pretty much all the same)
"Not at all. Much of the drama around the new MBPs was how anemic they look compared to other "pro" laptops. They don't even support 32 GB of RAM, much less 64. No ECC. No Xeons. No "pro" level graphics chips."
I'm a dev, I work on terrabyte size databases, though I may have liked to have 32 gigs of ram, the truth of it is I hardly ever am using even half of my 16. Sure seems to me most of the blame falls on good old Moore's Law no longer keeping up. It isn't Apple's fault that today's procs are only 25% faster than those from four years ago. The old retina's had the advantage of still being in an era of faster processor revs as well as being able to bring SSD's to everyone, which was also a huge performance boost.
What are the "pro" level graphics chips used for? Seems mostly games no?
Mark my words, all the brew-haha over the current gen will blow over in six to twelve months as type-c becomes more common and accessory makers get on board. Apple will rev in two years with more RAM, their fancier fitted battery and whatever the current gen proc is, but everything else will remain the same.