This question comes up often, and we knew it would today with the release of Egyptian Eye inlays....for guitar only.
The honest (aka brutal) truth is this: the money they would bring in doesn't justify the money it would cost to program them.
Bass inlays are a much bigger task than guitar inlays. You can't just slap the guitar ones on bass necks. The sizes and spacing would be completely wrong. Furthermore, you can't just use one bass inlay across them all. What looks right on an SSB 30" Scale Warhead ain't gonna look right on a Gecko 6-string.
Then you have to think about the fact that fancy inlays account for a small fraction of all inlays sold on guitar necks, and bass neck sales account for a small fraction of all overall necks sales.
All things considered, the juice just isn't worth the squeeze.