Great post, thanks for taking the time to share! And, interesting point about how well-run the architecture team was ... and how it wound up not mattering because of the relationships that senior management was pushing.
I have never seen team who only does architecture and no implementation ever succeed. You usually end up with lot of UML diagrams and PPTs that are unfortunately not executable. When "implementors" arrive at the scene, they realize all the things that had been overlooked from 30,000ft. Finally what gets implemented is either good with little resemblance to those pesky UML or terrible but in full compliance of "architecture". Avoid pure architecture teams at all cost.