Elucidus

This is somewhat true if you have a powerful enough ship, but you can't do it early on, the star base has too many defenses. Once your ships are powerful enough, it is likely theirs are powered up a bit and starbases are pretty easy to power up as well. If you are able to just walk through their territory destroying all of their bases then you should probably be playing on a hard difficulty level. It is a good theorycraft though and I do enjoy that, so keep it up.

Civ4 most definitely had multiple productions at a time*. There are quite a few 4x games that were built for this and I was always disappointed to find ones that did not,. It is usually that to get to that point or to see it you would have to either be building something really small (cheap) or have specialized to a ridiculous point. If you stacked the wonders in civ4 just right, yeah I was able to build multiple ships a turn from two different cities and that was actually p