Sorry, but I don't really buy that argument. By what you're suggesting, no developer on earth can get into coding APIs that wasn't in it from the beginning or something. If you offer lots of money, talent will come. One of Apple's biggest problems is that it keeps moving people from OS X to iOS and back again. It may take some time to get newer hires up to speed on the code, but the long term investment would be worth it if it means they can keep projects on track. I think there are plenty of say Vulkan developers that could be persuaded to either develop a version for OS X or work on Metal with a nice solid offer. Why work for free when you can make a lot of money? Some Linux developers might stick to principles, but many are doing it on the side with little time to put into it because they've got another job to work in order to pay the bills. I know I'd rather be making money writing music each day than working on industrial equipment, but so far I can't get it to take off.
In the case of OS X, however, I feel they have gone the opposite way. They're doing too many "major" updates that offer very little in "real" improvements, IMO. It also makes "macOS" unstable. Yet they feel this need to push something out every year anyway. I'd prefer they go to a two year cycle or release when ready. Microsoft is now following suit and people freaking HATE IT (because Microsoft forces updates). Apple doesn't force updates, but they do NAG NAG NAG on iOS (there is NEVER an "ignore" or "skip this version" option, always "install LATER" even when you don't want it EVER. And I mean like ONE DAY at most later. It ticks me off, personally). With OS X, it's been a lot better (so far) in that regard, but ultimately developers dumping support for older OS versions forces the issue sooner or later (or many people would still be using Snow Leopard).
That just doesn't excuse a decade of neglect on Apple's part. They could have (and should have) kept OpenGL up-to-date and graphics drivers up-to-date. NVidia can manage. Why can't the richest tech company in the world manage? You claim money has nothing to do with it and I call BS. Porting OpenGL isn't that monumental a task. Apple simply didn't give a crap about it or gaming in general and never has. Why they ignore what traditionally was a large market segment for Windows is utterly beyond me, especially after the move to Intel where getting good support wouldn't have been that hard. Quite the contrary, some companies complained loudly that Apple announced better support in 2007/2008, but then didn't follow through. Depending on things like slow Cider conversions on a platform that is already hampered by slow GPUs and outdated drivers just wasn't going to work. At the very least, they could have offered a "gaming model" (i.e. GOOD GPU) that would enable much better Mac gaming and excellent Boot Camp gaming.
There's nothing clear about it. It's Open Source. OS X runs on UNIX. The hard work was already done. All they had to do was keep the port updated. If open source developers can keep it updated, surely the richest tech company in the world could. If they had hired people in 2008, they would have 8 years experience by now.... Never hiring = never getting new people with experience since NO ONE is going to work on OS X if they aren't employed by Apple (unlike Linux).
Maybe the moderators hate tangents, but as the thread starter I don't mind them as long as they relate to the bigger picture of gaming on the Mac. In other words, Aspyr is simply one of the largest game developers for the Mac and hence I noticed their absence. The bigger question to me is METAL and whether we'll see more than a couple of titles using it. Aspyr, in particular announced support for it and hinted they might update some of the older big engines to use it as well if there was a big benefit. We're talking about a company that brought KOTOR 2 to the Mac last year (personally I love to see older titles appear for the Mac as they always have enough GPU power and it's one less reason to keep VMWare or another Windows machine around just to run older Windows games).
As a big thank you to the Mac community that made 20 years possible, you guys will soon see a bunch of fun news on what got us here, and where we are going. You'll also see one of the biggest sales in Mac gaming history.
