Could be. I don't think canon actually takes a stand either way so it comes down to personal preference. I like to think building new webway gates is mostly unnecessary and way to resource extensive when they do need to build a new one.
Ignoring the table top they really aren't. The Tau lack anything to really put down a Necron warrior permanently so a Lord can easily just order his mindless warriors to wear them down through attrition and eventually win. While things like Wraiths can phase through the ground and massacre them. Really I don't think the Tau have actually won a major engagement against the Necrons yet.
The big thing about Tau tech is it is advancing at an insane rate with their focus on forward thinking and total lack of fear of tech backfiring on them. I mean in 6000 years they progressed more then the Imperium did in 40 000 years.
Anyways Orks aren't an HS and it would be pretty easy to argue so as looking at them would reveal different tribal cultures and groups. Even traditions and superstitions. As well as important stuff like how they like to fight.