A lot of this control and insight into the µarch is gleaned by the public not from the hardware company's released drivers or docs but through exactly this sort

A lot of this control and insight into the µarch is gleaned by the public not from the hardware company's released drivers or docs but through exactly this sort of reversing. See Ager's website as an example. You could also take this to the extreme, as Stallman used to do with his OLPC where he deleted the wifi blob to only use lan because it wasn't free enough. If you have to wait for hardware company's to build free and open drivers and open hardware docs and open firmwares to use linux well im afraid your options are basically some X220 with a Open rom bios reimage. For now, Apple's arm64 silicon is the most compelling option for anyone that wants to develop on the architecture locally. It's the same way as how i386 was the most compelling option for anyone that wanted to run a free unix at home in 1991. It just does not matter that Apple hasn't done a dump of all their drivers and hardware docs because it is all we have and the hardware is damn good at that too.