I don't think any major platform that ever supported OpenGL or OpenGL ES--including desktops, smartphones/tablets, and web browsers--has actually removed it yet. Apple will probably be the first to pull the plug, but they've only aggressively deprecated it so far.
How exactly is it aggressiv? I'm selling games using OpenGL on iOS, iPadOS, tvOS and macOS, works with all of their latest hardware. I'm not getting a warning or any sign from them that they will remove support.
It was my understanding (which could definitely be wrong) that their OpenGL support is both behind the times--which is impressive since OpenGL has received no major new features AFAIK in the past decade, the topic of this HN post notwithstanding--and won't even get any bugfixes.
The last supported version they ship doesn't support compute, which is a pretty big limitation.