system
Given the following post, respond as if you're commenting on Reddit:
human
[40K] How long will it take for the Tau to surpass the other races in Technology?

Let's be frank. The Tau are not a strong race. They have the smallest empire of all the powers, lowest tier technology, and are constantly being raided by Dark Eldar, Orks, and the occasional Ultramarine.

Despite this, the Tau are the fastest advancing race in the galaxy. They've become star ship capable in a fraction of the time it took humanity. There weapons, while overall weaker still outdo anything Humanity had when they didn't have assistance from the Big E. Tau are advancing extremely quickly, so how long would it be before they are more advanced then even the Imperium or Eldar?
gpt
It's a difficult question as both the Imperium and Eldar are currently in periods of great decline and so what we see of them now is barely a shadow of what they once were. 

So how long until they overtake the IoM and Eldar now? Well, at the moment the Tau lag behind them both a little bit, but the difference is that they are advancing at a hell of a pace, while the Eldar are stagnant and the IoM advance only very very slowly. In a few hundred years their basic battle tech may be at the same level of the IoM and maybe a few centuries later the Eldar, but it's hard to say as much of their advancement has been unpredictably fast already. Maybe tomorrow they come up with a new design that takes them up to the IoM level, who knows? 

Where they struggle is in Warp tech, which they have little to no understanding of and maybe that will hold them back, but perhaps not. Maybe they can find a new way to travel that avoids the peril of the warp, but if not then it'll be a bit of a problem until they can work it out. 

So they will probably be on a rough level with current IoM and Eldar in a relative blink of an eye (in some aspects anyway), but getting up to pre-fall days of Eldar or Dark Age of Technology level IoM, well, that's a huge leap and it's possible they never will.