I've often thought of the Mac Pro and Cinema Display as simply advertising for the brand itself, comparable to elite sports cars auto makers have. They don't sell many of them but the tech in them sometimes filters down to lesser models furthermore they tend to attract a lot of attention to the brand. There's no reason to give up the Cinema Display or Mac Pro - just a lack of vision. Making solid long lasting computers at both the top and mid range level is an insurance policy that consumers will stay loyal to the brand. No coincidence as Apple shows a lack of interest in these areas users are questioning what's worth staying for.
Exactly - it seems pretty clear that Apple is no longer on board with the "trickle down" marketing approach. That is why I now have to admit I think the MP is eventually dead - they are only investing resources in the product that they believe they can leverage in MP sales as opposed to it being a flagship product for the rest of the line.
I have recently made the difficult decision to move from Logic Pro to Cubase and replace my cMP with a Skylake-X Windows 10 machine next year. Even if Apple does update the nMP, the cost will be astronomical (plus costs for external drive boxes). I'm staying on Mac for my general computing needs (which is now 100% laptop based), but affordable high-horsepower hardware and a commitment to the pro apps is obviously not in the vision for Apple.
I think the recent monitor announcement and dropping Aperture (and not demoing Logic at the latest keynote) are supporting evidence that the new Apple is more than willing to abdicate market segments if they don't think they can dominate a high volume market.
It comes down to I'm tired of feeling like it's NeXT all over again (I owned one of the pizza boxes too).