Quoting Wintersong, reply 16
The cost already increases for each ideology unlocked. That increase factor could be map size dependant (if it's not already).
The problem I see there is that there's what i see as a fundamental design flaw currently
The only way to bootstrap Ideology is entirely 'random'
You can only get them if you get Anomalies or via Planet Events. Anomalies are plentiful now because of the alpha, but will be toned back for beta. That means that your ability to bootstrap your Ideology is effectively limited. If you scale the ideology cost too high, you cant even begin a single tree effectively locking you out of the entire feature. If you amke it too loose, you can effectively mine all ideologies.
The other issue I see is that with only 3 ideologies, you efectivley are forced into one tree from the beginning.
By taking action into the galaxy, we get the chance to commit ourselves to the ideologies. Until then, it makes no sense to develop any building that allows to pursue ideology points (imho). No matter the galaxy size, planet distribution/presence and anomalies distribution/presence, we are going to get many chances along the game to earn some ideology points. And while in smaller maps the ideology won't go very far, in larger maps we can expect to develop it quite a lot.
As it works right now, you only get one ideology choice in each tree at rank 1. And all of them unlock an ideology building to get more points. Those buidlings are your non random (non interactive) way to commit your civilization into one ideology. Although at this point and alpha build, you can cheat and farm points to unlock all the rank 1 ideologies and get access to all the ideology buildings. Then farm the points of the idelogy you need (one ideology at a time).
The cost of each ideology rank may vary with time but I suppose that we are supposed to focus on one idelogy but we are given the chance to spread if we want to do so... just that it shouldn't be easy, specially the longer you wait for it. Not sure if that's the idea or if it'll change with time.
And I don't think you can miss the very first rank 1 of your first ideology. Events may be random, planets (that give you the event) are not. I must assume that the very first rank will be cheap enough that you can unlock it easily (maybe even the second unlock?). certainly, there is a lot to test/check about this topic. Poor developers. 