Doing so would enabled mainstream distributions to provide maintainable M-series builds, with all that entails in terms of stability, enabling choice, maintenance or security fixes.
The whole fork + dedicated distribution made sense at the start of the project since it provided a playground for quickly iterating and experimenting (which is a no-no to do directly in the mainline kernel or in a major distribution).
But Asahi is still the only Linux on Silicon option after all these years, which is a bit worrisome. Asahi should have been a cool but temporary initiative.
At some point, the project will lose momentum and for its accomplishments to last, it should be merged into the general effort, i.e. drivers maintained directly in the Linux kernel, and the userland stuff made to be easily packaged and shipped by mainstream distributions.