Not sure you are a developer or not, but I think your expectations of development are not accurate. Especially since this a AAA studio. Changes would need to be code reviewed, tested, etc. Then a release candidate made and that is tested. For Civ, we know there are different platforms as well so the package needs to be transferred to the porting studio. To give the porting team time to work you need to cut your release candidate weeks early. If there is a bug along these stages you have to fix and do it all over again. It's not like they finalized the build that we got today just yesterday.
Additionally, this is a minor feature patch. In software development it's common to have multiple branches, I doubt every single dev is working on every single patch together. There probably are only a few devs on these smaller patches, since the bigger ones, (Civ releases) would take more time.
Another thing to think about, after changes are made, someone needs to play test them to see how they feel to the player. So even if changes were made in 1 day, the product needs to be verified as enjoyable, which could take countless additional days.
Just a perspective to keep in mind. AAA studios probably have more processes in place as well, which hinder quick turnarounds.