I don't remember if it was in the article of Discord, but I think Blair clarified that late game you can use refineries as TEC to get at least some of these rare resources. My guess is that they're intended to encourage early game exploration and perhaps prevent rushing/spamming certain key units until the late game.
Very cool if that's the case, glad that the devs are steps ahead of me if true
Also hopefully things like that aren't TEC exclusive lol. I'm sure they won't be cause that'd be kinda silly.
Even things like trade routes being TEC exclusive(?), it'd make sense if the Vasari & Advent need to research it (since the Vasari are on the run & the Advent are on a crusade of vengeance) while the TEC start off with trade and trade routes already (since their society is initially built on it) and the V & A only turning towards more permanent forms of economy when they start to grind to a halt against the TEC & each other. Idk I'm getting off topic kinda, running my mind off random lines I've read here and there.
Gotta try and stay cool 'til the technical beta goes live lol.