As some have noted already, the only one taking responsibility here i Aspyr Media, the ones responsible for the Mac App Store-version.
They released this statement on their blog March 13th:
We are seeing a lot of users with problems playing SimCity Complete Edition after updating to MacOS 10.13.
We are looking into the issue now and hope to have news soon.
We will update this article with news as it becomes available.
Thanks so much for your patience. – AspyrJason
I just DM'd them to get a progress update, and they answered:
Hopefully, as with Civilization for Mac on Steam, EA will also implement Aspyr's Mac App-store update when it's ready – but, as you know,
As of now, we need to be patient with Aspyr and hope for the best. I 100 % credit Aspyr Media for taking upon themselves the responsibility that clearly noone but
xoxo