From what I have read, it is Apple who decided to stop support for Macs openGL. Now that the game's engineers will have to work with Metal, I guess it is in the move to also terminate the support for the 32 bits systems. I have often read that the game was kept low on technical demand because players had low-end computers. I think this might not be a decision driven by desire from the game's team, but just a case of the computer market.
Now, a lot of players were complaining about the low technical demand of the game because they had invested in a better computer and the game was barely demanding. So now, may be they'll get a game that needs a little more "power". May be that'll be a good return to their investment.
I know this will be a heartbreaker for some players, but they'll be able to play the game as it is now. I think if we ask for a game that does more, we need to have computers that can take more. That's a simple equation.
I hope this is comprehensible, because English is not my first language.