Going back to the intel FUD paper, if you consider volume shipment as success as in their document, uboot looking thing with FDTs are the most successful paradigm by orders of magnitude.

The kind of systems using FDTs aren't going to switch I don't think. I have to imagine that ARM64 UEFI was done for marketing and by clueless product management. The CPUs and integration of ARM servers have been so pathetic, nobody was buying, and they were fumbling around at this level while ignoring the elephant in the room. TX2 and Centriq are the first realistic implementations for general purpose servers, and now they are unfortunately saddled with UEFI and ACPI.

This was a rare 2-3 decades kind of mistake. Not a lot of software gets that privilege.