Thankfully long before that. I recall Diablo 1 was released for Mac OS (9?) only a few weeks/months after PC, and Warcraft I and II had full Mac Support!
IIRC it was't purely a post-release-port, they did have parallel development tracks before anything was released and for some titles they didn't want to risk the upfront cost for the relatively small percentage right away.
Warcraft 2 was my first experience playing a cross-platform network game. I was on a PC and I dialled in to my friend’s Mac. Understanding how things are architected now it makes perfect sense, but as a kid my mind was blown since I considered these to be wholly incompatible platforms.
Except for Overwatch, RIP. Also Diablo 3 has always run terribly on MacOS. Pretty much only WoW runs decently. Maybe Starcraft 2 used to be okay but it since became way worse.
Yep, oddly enough they made the game engine themselves like they did with almost all of their other games; apparently this time they didn't make it cross-platform.
Pretty strange considering the other (arguably more complicated) engines were supported from day 1, even their unreleased FPS (Ghost?) was going to be launched like that.
I'd LOVE to have a native macOS client for Overwatch. Since I upgraded to a 2019 16" MacBook Pro, my eGPU no longer works in Bootcamp due to the dreaded Error 12 and I can't resolve it. My eGPU works flawlessly in macOS. Plus, I hate using Windows and want to avoid it if at all possible.
You can fix Error 12 by using an eGPU loader in UEFI (you can just put it on a USB drive). The problem is that Windows sets the PCIe address space wrong and then it can't properly talk to the GPU anymore. It happened during one of those large Windows feature updates last year. You can find setup and documentation on egpu.io, goalque is the author. (it's called something like automate-eGPU EFI)
Odd, the EFI loader puts the eGPU in a fixed space that always works (mainly because it no longer looks like an external GPU to the rest of the system), and Windows can't mis-configure it anymore.
Blizzard has always been good at supporting Mac's, even going back as far as Warcraft 3.