Look at Mesa release notes for example, there's a steady stream of driver feature work and bugfixes for GL: https://docs.mesa3d.org/relnotes/25.2.0.html (search for "gl_")
A slow moving graphics API is a good thing for many uses.
People are writing new OpenGL code all the time. See eg HN story sumbmissions: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...
It's not slow moving. It's completely frozen. The Mesa guys are the only ones actually fixing bugs and improving implementations, but the spec is completely frozen and unmaintained. Apple, Microsoft and Google don't really care if OpenGL works well on their platforms.
but, literally this article is about something new that was added to the OpenGL spec
I suppose the same is true of Direct3D 11, though. Only the Direct3D 12 spec has been updated in years from what I can tell. (I'm not a graphics programmer.)
As a sidenote, I've very much enjoyed your blog, and developed a similar handle system as yours around the same time. Mine uses 32 bits though - 15 for index, 1 for misc stuff, 8 for random key, and 8 for object type :^)
From macOS 10.7 to 10.9, you'd get an OpenGL 3.2 context. As OpenGL 4.1 is backward compatible to OpenGL 3.2, it's fine that the same code gets OpenGL 4.1 now.
Basically, macOS will provide an "old" API to programs that need it, which is fixed at 2.1, and a "modern" API to programs that know how to ask for it, which has settled at 4.1 and is unlikely to change.
OpenGL 4.1 is harmonised with OpenGL ES 2.0. Almost the same rendering model, features, extensions, etc. On iOS, iPadOS etc you can use OpenGL ES 2.0, and no version of OpenGL (non-ES), so my guess is that's why macOS settled on OpenGL 4.1. Both platforms offer the same OpenGL rendering features, but through slightly different APIs.
But if you request 4.1 over GLX (which uses X11/Xorg/XQuartz), the X11 code only supports OpenGL 2.1. For example, if you're porting some Linux code or other GLX examples over.
Unfortunately, the GLX limitation with macOS is probably just due to the Xorg-based XQuartz being open source but very minimally maintained. I looked at the source, and the calls and code paths are almost there for 4.1 support. It uses Xorg and Mesa, which have all the bindings. The standard function for requesting a 4.1 profile, glXCreateContextAttribsARB(), is even in the library and you can call it, but the extension flag GLX_ARB_create_context is disabled, and requesting a 4.1 profile (or 3.2) still returns 2.1.
In other words nothing changed. The OpengGL standard had been well past 4.1 for years when Apple released Metal. People working with various 3D tools had to disable system integrity checks to install working drivers from NVIDIA to replace whatever Apple shipped by default.
The last OpenGL release 4.6 was in 2017... I think that speaks for itself ;)
And at least on macOS, OpenGL is officially deprecated, stuck at 4.1 and is also quickly rotting (despite running on top of Metal now - but I don't think anybody at Apple is doing serious maintenance work on their OpenGL implementation).