I think "there is only one person working full-time on maintaining Linux input libraries and he's overworked" is probably a decent excuse. I don't know what you plan to do, but I would advise against forking unless you can hire a team to accumulate testing hardware and work on this for multiple years. What we have seen too often is these forks just fizzle and get forgotten, especially if they are only focused on getting one feature to work on one very specific device.