Yeah costs do go up for sure. The issue here is that the early game advantages afforded by GPT + no-penalty civics are far more important than anything later in the game. In other words, what you do in the early game will have a bigger impact on your game than what happens later. It's not right to claim that there is a 1:1 relationship between what happens early game and what happens later. Just because you will spend a lot of money later on civics, doesn't mean you need to boost them earlier. The early boosts have a much bigger impact/cost ratio. You can basically use the civics for early game advantages, then technically abandon the system altogether having already received the boost you needed unless you can afford it. The maintenance system can be good to keep advanced civs in line. I don't think it should be changed. The only changes I would suggest are removing the GPT bonus from the default civics (retaining the happiness modifiers) and adding some penalties to the early game civics. If it's preferable for the default civics to have a bonus, then GPT is the best option. Giving civs 1 of each yield would have a much bigger impact than 5 GPT would as some yields are worth more than 1 GPT ( Production = 2 Gold for example).