I think the OP is missing a few very big points with his argument.
First off, you say that with indie games Mac makes up 20% of sales generated. Well, good for them.
Never. Not once. I never even alluded to it. I'm not sure what you read, but I never said Mac makes up 20% of the indie market.
That doesn't mean that 20% of the population here is filled by Mac users, and those who do use mac and shop here, are already going through the process of converting the games anyway so they can use them. That's not a 20% increase of sales if those people already have the games, and it's not a 20% increase in sales when the number of people involved in the indie game community aren't in this one.
Again I never said 20% was anything more than an example of potential revenue for a minimal investment.
Next up, market share... okay, big deal. Mac's beaten Linux. But then, Linux had a fairly small market share too. Linux looks interesting as all get-out, but I'm not willing to take the time to learn to use it while I'm busy in school. That again doesn't mean that there's a flood of people waiting to purchase games here. This is the same mistake you made with the 20% comment, you're equating the total population to be the same in this one. So, it's X = Y, but Y =/= X (Meaning, all users on this site belong to the total number of computer owners of varied OS, but that total number does not exist on here).
There is no extra support since the platform is virtualized inside the DOSBox emulator. GOG picks the release like they do for any of their current releases.
You also say it's minimal work to convert and make the games accessible to Mac Users. Good, then it's minimal work for you as well. GOG is staffed by a small group of people, and for them to go about converting every game on this list while managing new games, tech support, issues, the forums, so on, would take a fairly long time without some added help. It also means doubling up on the bandwidth usage to support two versions of the same program, which may kick up costs on us.
Yes DOS games are just *HUGE*... good point.
Next up: "Making this games OS X Compatible opens up a lot of possibility for GOG to market products in the Apple Application Store ect. ect.". Somehow, I don't think Apple supports anything that isn't.... an application, or a direct game, while this site is basically one large service. Plus Apple probably takes a cut of the profits on anything sold. It's easier to just do what they're doing now.
In any case, things aren't likely to change unless we wind up with a very large part of the forum advocating the switch. Not to be a drag, but that's economics for you.
Wow. Everyone is so jaded. God forbid someone suggest something.