system
Given the following post, respond as if you're commenting on Reddit:
human
[40K]What's to stop the Tau from becoming a major superpower?

The Tau don't seem to have a major flaw like the Eldar or the Imperium (Eldar have a declining population and the Imperium has stagnant technology) so what's to stop them from becoming one of the most powerful factions?
gpt
Numbers.  What the imperium lacks in development it makes up for in bodies.  You have battle Mechs that can challenge space Marines?  Ok here's 50 guard battalions.  Deal with that.  Maybe they're not as well equipped but artillery is artillery and they'll eventually will through shear weight of numbers.  

You have an Armada?  That's cute, because imperial have world's have local militia navies with more ships.  

The only thing the tau have going for them is that they're not on the radar of the imperium as far as xeno threats.  Once they are?..... They'll be crushed under the millions of guard corpses that the imperium will find at them.