This one is very odd, why did GOG do this?
Sorry to revive a older thread, but from the history point....
I have little experience with the Macs. I while back got some old 2009 Macbook Pro's and couldn't of course do anything with OS X 10.4 Tiger, 10.5 Leopard and 10.7 Lion whatever... So I installed Linux, that I anyways was going to use.
I did experiment little with the OS X, as that was at the time when those were brand news that I had used them.
I have not used Macs ever as my daily computer. Always had PC, and mainly Linux and Windows for gaming.
But boy did I really fell to rabbit hole.
I have always personally disliked OS X. I do recommend it to many, as it fits for casual users very well, if not being best choice for many. For me? Never been a big fan after some time of use. I want to like it, but can't with such a mentality.
So, I thought that of course I can install gog client and get some old games to run on it. Boy was I wrong. No client for that. So download every game separately. I believe that is only way to do it, but I didn't proceed with that.
I spent days to hunt ways to get common basic software running to make the unsupported OS X versions working, like get some LibreOffice, Firefox and so on.
I was really hating the whole thing.
Then I found that I can get latest OS X to unspported Mac. Of course it would fix the problems to get steam, gog clients etc?
So off I did go... Writing this on such iMac...
And when I had Steam installed, I get warnings "32bit is not supported".
And here I am, with new OS X so that I can run Steam and GOG clients.
But OS X doesn't support anymore 32bit so all old games are obsolete.
What good is it to not able get GOG client for High Sierra, or 11.4 (IIRC) that is last OS X that supports 32bit apps?
I really see only way to install Linux, and be happy that I can run everything old and new on that one. Backward support is a critical thing for old gamers!