Before voting allow me to explain.
Do you think the Tau are at a higher tech level than the Imperium? That is they have discovered more of the mysteries of science.
Or do you think they are not? Instead what they have so far discovered they intelligently and innovatively apply. A comparison would be iPhones vs other technologies

The iPhone isn't technologically better, but does give, by all accounts, a superior user experience and allows people to pick up and use it successfully far more quickly.
The Imperium has fantastic technologies at their disposal. Their starships are better than the Tau for instance, the Tau can't come close to stuff like titans (forget how silly they are for a second), instead use spaceships that must have the crews sweating as they try desperately not to crash all the time. The difference is the Imperium understands none of it. They manufacture the same items for 1000's of years, knowing only how to load the ammo and pull the trigger, no doubt after saying a prayer and bathing their left hand in incense before removing their left shoes. The Tau can take inferior technologies but apply them correctly for a superior end result, improving out any design flaws. For instance they might not have macro cannon armaments on the battleship, but would have an automated loading system for the railcannon that was a darn sight more efficient than a hundred sweating men, not to mention easier on the logistics.
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