strange, I'm on Mac, and it works fine. I'm on 10.13.6 High Sierra. I think that there might be problems with this game and Catalina update, though, but I'm not sure. I'm on Ghz intel core i5 as well, so that is probably not part of the problem.
I'm assuming you meant to post this in the Empires of the Undergrowth forum since Ecosystem isn't for sale yet.
There's a beta out now that should fix the game on Mac (but we haven't been through the notarisation process yet, this could take a while), an update to which some weeks back caused issued. Follow the instructions in this thread on Steam if you'd like to join the beta test, or simply wait a short time (the update should go live for everyone in the next day or so):