There are two levels to this:
Kernel development / HW specific support. This is mostly being done by people unrelated to any distro, or unrelated to Pine64 at all. (linux-sunxi community, Google, linaro, bootlin, lima project, libreelec, and various individuals) One exception is Martijn, who did initial bringup for Pinephone Pro, and Mobian's maintainer. Nevertheless, vast majority of ongoing improvements, bugfixes, and HW support work comes from outside of mobile distros, and always did, even the work focused directly at the Pinephone SW support. And these efforts were not supported by Pine64 in any comparable way to how distros were supported initially.
Then there's userspace application work, and integrating all the normal user facing SW into a cohesive whole. This is where the distros come in. I don't know much about struggles with that.
So yeah, don't forget that TFA is just a view of one person, and the sky is not falling. (well, aside from the war, and energy crisis, ... but hey)