Hmmmm, I see your point. But Mac Pro has always been TWO things in my opinion. Their top of the one system...but ALSO...Apple showing off that they're still the most innovative company in the computing world.
Like when Jobs got on stage and pulled the MBA out of an envelope and said that it was the key to the future of Macintosh. Or the can't innovate my a** commentary when rolled out the MP 2013?
To position the the bulk of Apple's Mac technology efforts are solely grounded in the Mac Pro updates is to largely miss the mark. Apple has plowed lots of technological moves into the other system in the Mac line up. The Mac Pro 2019 didn't get T2 first. Didn't get AMD 580 GPUs first, Or the first Vega GPU. It lost the optical drive just like the whole rest of the Mac line up. Throughly integrated Thunderbolt just like the rest of the Mac line up had done years before. First PC tower to have GPUs hooked up in a NVLInk/InfinityFabric class link? Nope. An internal USB socket? Hardly revolutionary.
Mac with RAM mounted on bottom of logicboard... done on Mac laptops before.
Yes there is some 'new' things on the Mac Pro 2019 but the scope isn't that broad. The CPU and GPUs all have references designs for Apple to work with. The CPU and GPUs themselves are not upfront directly funded by Apple. The Plex PCI-e switch was a product pulled from server implementations and admittedly insightfully 'repurposed'.
The MPX socket is a naturally evolutionary path from the full custom socket on MP 2013 cards that sent DisplayPort to the distant TB controllers and got rid of discrete wires for power. If move some TB controllers back to the card while still needing to send DP off , that really wasn't a huge leap. Drop the proprietary aspects of the PCI-e feed for the GPU chip and it is substantive engineering work. But huge innovation is a stretch.
There was lots of engineering to do, but Apple product constraints paint almost every Mac product into a corner on some aspect that some clever engineering tapdancing has to try to mitigate.
And with the 2019 Mac Pro, I would argue this is the most innovation Apple has demonstrated in the pro market in a VERY long time...
The VERY long time is actually quite indicative that large amount of Apple technological time and effort has been spent elsewhere. To a very large extent the MP 2019 was just playing "catch up" as a jump from a 2010 MP to a 2019 one. If measure the 2019 against the other slot boxes Apple released from 2014-2018, then it isn't hard to win the race of "Most innovative". Apple's Mac sales had grown quite substantially in that nine year gap without an "expensive as possible" slot box to 'lead' the line up.
and to just let it die a handful of years later would be an extreme disservice to the ingenuity that went into the damn thing IMO.
Afterburner 'solved' a problem that M-series has now taken off the table.
T2 ... same thing.
MPX connector ... very similar issue. ( and Apple sank probably an order of more magnitude more money into developing UltraFusion. So if it a lament sunk costs contest ... that is even bigger thing. )
If Apple provisioned out two x16 PCI-e v4 bundles from some M2 SoCs for the Mac Pro Apple could probably reuse :
1. The Plex Switch baseline purpose. Not as many slots but could provision out several slots to keep some legacy PCI-e v3 and v2 cards happy.
2. The case and space frame are all likely highly reusable even if chop the height in half. Same general 'look' and pull off handle. Could even keep around the 'innovative' $100/wheel rolling option.
Most of the fans and dual sided logic board could be kept also. ( One less big , 'front' fan ).
Could probably tone down the 1400W power supply but the format where the backside fan has side effect of cooling power supply doesn't have to go away.
3. SSD modules are still in the Studio ... ( like the iMac Pro and Mac Pro). Same thing likely coming.
4. They'd need to toss a discrete SATA controller on the logic board but the USB+SATA+SATA port thing could stay.
If there is still a "void" inside and distance to SATA sockets is the same , then folks could transfer their Promise J2i brackets.
5. The I/O card thing would work with adjustments. ( just retimers now instead of TB controllers. ).
The notion that the only innovative thing Apple did on the MP 2019 was the GPU MPX modules is rather myopic.
if Apple swapped two M.2 SSD sockets on the 'backside' for MPX connectors on the front there would be same fans of that "no innovation" change. [ get past the one ,and only one, drive support out of the box. ]