If you're Pixelmator or Apple's own Final Cut team, sure, use Metal. For anyone else that wants to make a living, supporting multiple platforms is a given, so you won't pay the slightest attention to this deprecation notice.
If you're Pixelmator or Apple's own Final Cut team, sure, use Metal. For anyone else that wants to make a living, supporting multiple platforms is a given, so you won't pay the slightest attention to this deprecation notice.
Actually, most game developers do that. Pretty much every game (even ones with a custom, "non-AAA" engine) will have some kind of abstraction layer for dealing with graphics API's. Writing an additional backend for Metal is not a monumental undertaking -- it's a tiny fraction of the overall code you will end up writing. Also game consoles, for the most part, use their own graphics API's which are not portable to desktop PC's.
I'm sure the Mac version of these tools aren't used by any studio with more than 5 people, but independent contractors, small studios, and individuals working at home really benefit (or else they wouldn't have bothered to port and maintain up until now).
I really like the idea of creating more space for the little guy. I want them to do well, but honestly I haven't had the best experience. As someone who uses the professional tools during the day, but has only the occasional needs for personal use I was happy to pay for a Mac-only tool. In practice, for a tool I only grab every few months I often find there was a regression in some feature that I guess is only used moderately often (selection boxes), it doesn't currently support that feature (I can't remember, but it was something like HSV color space, more than 8bpp, or some file format like TGA or PNG--not features you'd add to v1, but nothing too obscure), or there's another paid upgrade.
Even beloved Mac tools like Panic's Transmit, I feel like I can't 100% rely on. At a moment's notice I'll have to jump to something else to finish the task.
On the other hand, they definitely made it harder for developers to create a new game engine.
However, where it will have major effect is availability of any professional software. Such as CAD. Mac has always been a pain in the ... platform to support because of their weird "Unix but not quite" ways of doing things and now there will be no justification to support it anymore, especially in the OSS sphere. E.g. I fully expect things like KiCAD (and also the commercial Eagle which has Mac support) PCB CAD to disappear from Mac as soon as OpenGL is removed. Nobody has resources to rewrite such software to use Apple-specific Metal. Another such project is OpenSceneGraph, a large building block for 3D visualization and simulation applications.