It could be because coding this is a hobby that has to take a back seat to work and family...
Add to that having ensure that the rewrite from scratch doesn't trash peoples worlds, break their AE systems, or lose their EMC stockpile. Reverse engineering another mod to figure out what that mod changed that broke this one and figuring out how to patch a fix into it at runtime. Tracking down and resolving performance and tick rate issues... And of course testing all of this.
There is a lot more to writing a good mod than just the writing of the mod.
Its easy to write code. Its not so easy to write good code.