I feel like at this point you can no longer afford to generalize about the market this way if you're a game developer or publisher. The gaming industry is so big and so incredibly over-saturated with games that it is better to evaluate the market for your game, individually, rather than gaming as a whole.
For example, games like Factorio are incredibly niche and loved by people with builder/engineer mindsets (not necessarily working as engineers). Now you've got to ask yourself whether potential Factorio players are more or less likely to own a Mac, compared to the 3% (cited by another commenter) of all Steam users on Macs.
Also I wonder how this 3% figure was calculated. Is it based on monthly active users? I am a Mac user and I have Steam installed but I don't leave it running all the time because application itself is a dumpster-fire battery hog. I only start it up when I want to play a specific game, then I shut it down. Some games don't even require Steam to be running so I launch them directly without bothering to start Steam. Am I excluded from the monthly active users because I might go months without launching Steam, despite playing games regularly?
For example, games like Factorio are incredibly niche and loved by people with builder/engineer mindsets (not necessarily working as engineers). Now you've got to ask yourself whether potential Factorio players are more or less likely to own a Mac, compared to the 3% (cited by another commenter) of all Steam users on Macs.
Also I wonder how this 3% figure was calculated. Is it based on monthly active users? I am a Mac user and I have Steam installed but I don't leave it running all the time because application itself is a dumpster-fire battery hog. I only start it up when I want to play a specific game, then I shut it down. Some games don't even require Steam to be running so I launch them directly without bothering to start Steam. Am I excluded from the monthly active users because I might go months without launching Steam, despite playing games regularly?