Yes, that appears to be it. The age mechanics has no reason for being other than game balance. At this time, I support it. If you give new players too many options, you might get many that find something that they could do that could be really powerful if pulled off, but they would make the mistake of not covering what they need to survive that long. Think trying to min/max but getting it wrong. The age system is a brick wall, one that will at least force the player to make one or more other choices before moving on.

Skilled players know what to do and what not to do, so they don't suffer from this problem so much, but this system helps with the learning curve. Everybody is a newbie at some point. Plus it helps to prevent players from racing to planet invasions. In GalCiv 2, I found that it was a hard tech to research (its expensive), so it is temping to avoid it if you don't need, because you could research many other things instead of it. However, if you catch yourself in a war without it, it was a real pain to try to get it. I think that keeping planet invasion in the second age without it being an expensive tech does help to improve things. You can't race for it on the first turn, but when you need it, it isn't that hard to get.