That's why I liked my friend's idea of putting them both together. You have to unlock one to get another, at a steep cost.
I mean think about it, we're talking about one of the most important aspects of the game here: Economics. It doesn't matter how much Knowledge you have if you can't build your army, your defenses, and your base.
Why should it be cheap? Why should its price be comparable to anything else?
The game either needs to be changed in a way that you don't need upgraded economics to win (whether in the form of Harvesters or Econ Stations), or that upgrading your economics requires a huge sacrifice. Otherwise you've eliminated a lot of the strategy from the game by forcing a decision on the player that they can't avoid, unless they want to spend 50% of the game watching Netflix.
I've personally imposed my own rule that I can't build upgraded Harvesters, and it makes the game a lot more exciting. Still, I find myself just as reliant on Econ Stations as I was on the Harvesters, which is just another form of (more dangerous) economic dependency.