100k? You are funny! :D
The problem is, I don't have a Mac and never used one. So, I have no idea how that stuff works. We should be happy that Unity makes it possible for a solo developer like me to even provide a Mac version.
Regarding code signing, I started now with Windows to apply for a certificate. But it takes ages to get handed out or I have done it incorrectly. Let's see. For Mac I don't know, if it's even possible to do, without having one myself, but I haven't looked much into it, yet. I am still fairly new to everything.
There are not many people downloading the Mac versions and even less contributing. I'll try to do my best to keep the Mac (and Linux) versions working for all of you, but it takes away time from developing the game, which is what I want to do. I don't want to sell the game, I want people to contribute to the development and to share it.
I have sent you a mail regarding your Mac troubles.
[Edit] I just realized, that you were probably referring to the App store with the 70%. I was referring more to the "App cannot be opened because it was not from an identified developer" - in Windows you can rid of this kind of stuff with paying something like 100 bucks for code signing. Yes, it gives you a tiny bit of safety, but it's not worth in the slightest the amount of money imho, at least not for me.
Regarding app store fees, the 30% grab by Apple or Google is absurd and only possible due to a duopoly that should be fought against as hard as possible. If I can, I'll never sell something on such a store. I won't have a mobile version any time soon anyway. So that's easy to say :D