They did, when they adopted OpenGL and OpenCL. Years ago.
Apparently they've decided that those have outlived their usefulness.
Yes, and this was so much against their DNA that it required the chutzpah of a Carmack to get the Apple's CEO to implement the decision.
Apple is and has always been a strict leech on open ecosystems.
They try to build closed proprietary stuff first to lock you to the platform, and when what they build is bested by OpenSource, embrace it and move on to the next opportunity.
They did the exact same thing with BSD: grab a beautiful piece of OpenSource tech, bolt on a metric ton of proprietary closed source tech on top of it, and call the whole thing open source to get love and applause from the OSS crowd.
Techies are essentially a gullible bunch.
Nobody has USB-C stuff everything. Every owner is using a collection of dongles and it is absolutely stupid.
The OLED bar is also stupid.
I just hope my 2015 macbook never gets obsolete because I dislike the newer ones... and yes, I owned one, and I sold t after 2 weeks and got my 2015 back