Personally i believe there will always be custom forks of Kodi as there always has been. Kodi in general is written for such a wide variety of OS’s and devices its just way to much work trying to make it excel on them all based on one build. I know thats what the attempted direction they are trying to follow but others will always fork it and make attempts at making it work better on their own devices thats the great part about open source software.
Matrix Alpha’s are already up and basically working beyond the currrent level of the Official github revisions and will only get better along with the Official sources moving forward but its still to early for Matrix to see where Amlogic will fall looking forward. a lot hinges on the sucessful completion and release of projects like Lima and Panfrost and a couple of still private developments in the GPU area regarding Arm’s GPU’s being currently used.
As adamg said i don’t think theres much to worry about at this point in time…