From a Doylist standpoint, the Tau are kind of a metatextual joke. In most sci-fi like Babylon 5, Stargate, or Halo it’s humans from earth who go from cavemen to starships while the space aliens stay technologically and culturally stagnant, but in Warhammer 40,000 it’s the humans from earth who are the ancient decadent space empire and other younger races are inevitably going to overtake them.
Since the Tau fill the “humans” role in the scifi race archetypes for WH40K, it’d be neat if the Demiurge faction of the Leagues of Votann were like the Star Trek Enterprise-era Vulcans to them. The older more advanced race who know how the interstellar politics games are played and can offer guidance.












