I kind of agree with those that said that the ages don't exactly solve the snowballing. It's a half-built house. The chapters, or what you can call level design, are now watered down to make it feel more like one run, with mini-setbacks. I think this works for Civ7, but has to be redone somewhat for the next iteration. The ages mechanic, in my eyes, will likely stay, as it provides the backdrop for selling additional content. It also breaks up the game into sessions that people can tailor for single/multiplayer. However, in order to really prevent snowballing, the design should actually lean even more into separate level/chapter design than it does now. The reason ages are not well received by some is the setback of the player. If they, however, let you "divide and conquer" within a geographical subsection of the global map during antiquity and then place you into a much enlarged universe with boosted AI players, it would prevent snowballing. Imagine an Old World like antiquity that does not stop after 200 turns but lets you enter the next level, aka age, with additional civilisations on a larger map that pose a new challenge. It's game design of leveling up and finding a bigger enemy, instead of artificially reducing the player's ability.