somewhat contrary to all those who say don't rush take your time.
Well, taking your time is the path of least resistance. You can effectively have infinite resources by never aging up
Each age should be balanced as much as possible not just the later ages.
I would say the early Ages are balanced. What unbalances things is once things snowball. The pace we set, use of Advanced Great Buildings, and powercreep in Event Buildings all contribute to this.
Sure, I camp some ages for a month or two but who doesn't
Sure. I do like to take my time in an Age too. Mostly so I can get all the diamonds in each Ages Quests. But once you have that snowball effect going.... you don't actually need to camp for a month or two. Once you have a solid foundation, you could get through most Ages within a week each quite easily, and have all the resources you'll ever need from those Ages. Once you get to the Arctic Future and above the bottleneck will be with the Special Goods. It's only if you haven't got a sufficiently developed city that you'd struggle to do so
Of course not all players would have the experience necessary to get through Ages quickly (and easily), that's why it's recommended to take your time. A new players isn't going to have the same understanding of game mechanics that a vet would be able to utilise. If you're rushing then you also need to be planning on what to get / prioritise on your current Age before Aging up.
From where I am playing the distribution of expansions is biased towards the higher ages or veterans with the exception of the first few ages.
I don't see how it's biased towards higher Ages except the very last Age, Space Age Jupiter. If anything it's more biased towards the Ages upto and including Industrial Age. After that it reduces the Expansions per Age release, with Space Age Jupiter being the one exception right at the end. Those that appear to have more are actually multiple stages, and have to be completed in stages due to the Special Goods.
But really, here's the thing. Even if they doubled the amount of expansions available for every Age... you still wouldn't have enough. Not because it's "not enough", but because there'll always be something to fill whatever space you get.
Biggest reason to be conservative in the rate of adding more expansions: bigger cities struggle to load the game for some players without crashing. So if peoples devices can't cope with what's already there, then adding more space will only make that problem worse by adding more stuff that has to load
By slowing down the rate of new expansions, it gives a longer period of time before devices have to be replaced or upgraded to keep playing. Hopefully at a time the player would have already been looking to do so.