| Perpdepog |
I doubt it's from lack of interest, and more to do with the amount of effort it would take. Starfinder has over a hundred species to play as now, I believe. That's over a hundred different ancestries, each taking four or so pages, that would need to be written up.
Though I'm also guessing you don't literally mean ALL of the species in Starfinder. Even there we still run into a few issues that I see lots of folks on the boards go back and forth on. Multiple sets of arms, for example, and how they interact with holding and readying objects and the like.
And finally a majority of species in Starfinder simply don't have a whole ton written up about them. SF favors a wider approach to species write-ups to simulate that cantina feel of running into all kinds of aliens. 2E's approach is more about digging into a single ancestry that is supposed to have multiple subgroups and ethnicities.
(Not to say that Starfinder's species haven't also got subgroups, but it's less likely they'll all be brought into play when characters are zipping from star system to star system.)