So, I know we’re in the App Store, Google Play, Amazon, Steam, Chrome Store, and CoG Web Store.
Any others?
I don’t know a lot about Macs, but, is the Mac App Store different? (I’m pretty sure it is) And, are we not in it? (I’m pretty sure we aren’t) And, how does a Mac user play our games then?
Not the chrome store anymore. 
It’s gone the way of the kindle apps. And the games were in the Windows Store but not anymore.
As a Mac user I normally buy the games on Steam or through the App Store (I play them on my iPad. I like being able to see my stats at all times)
But do HG titles make it through the Steam? 
Yes. I don’t know how they work that out but I’ve seen both Story of Steampunk and Community College Hero on Steam so I’m sure other Hosted games are there.
Hosted Games with a proven track record go to Steam. I’m proud to say that the Lost Heir trilogy is there, and that Life of a Wizard and Life of a Mobster will be going to Steam when Lost Heir 3 releases in a few weeks. 
I’m curious as to why the games aren’t on the Mac App Store though, since it seems like a logical extension of the regular App Store.
They rejected our apps as being “of no lasting value.”
Huh. Their loss.
To be clear, they only rejected one of our apps as being low-value, but it was a bunch of work to support all of the Mac App Store requirements, and they included a lengthy review period (like the iOS App Store, but even longer).
Up until very recently, we even still had a few CoG games in the Mac App Store. Apple then said that we needed to do some maintenance work on them or the games would be pulled from the store. We did the math and found that it wasn’t worth our time to fix the issues that they reported, so the apps went down.
Just gotta make me buy several versions of each title to support you, huh? 
If I have 3 Life of a Mobsters can I play a “To Tell The Truth” version where my characters fight to see which is the real one?
lol.