Yeah, it's easy to grow from nothing as the saying goes ;)
Depending on region and target audience, Macs show up between 1.5% and 3.5% of total player base in tracking (see Steam and Unity hardware surveys, and I also see those numbers in our own games), and these have been the same for 10 years. For comparison, Linux is between 0.5% and 1.0%. Most Macs are laptops with Intel GPU which are simply too weak for most current games. The Mac OpenGL drivers have a legendary reputation for being crap since they are controlled by Apple, not the GPU makers (although, native Intel GL drivers are not much better). Sometimes the reason is simply that the additional required customers support for Mac costs money and thus the development effort can't be justified.
I'm a daily Mac user and like it pretty much, but for games I also have a proper PC, attached to the TV. Most games I play there would run at most with 5fps on my MacBookPro.
Sadly it is true, MAC GPU's are often the same hardware used in laptops. Also, Apple sprinkle a special kind of awfulness onto their drivers.
I tested this with Quake III (a game from 1999!). My 2011 iMac could not render the game at 120fps, it managed somewhere between 50 and 70. I bootcamp into Windows, and I get a rock solid 120fps.
They certainly are. Look at the current top 10 for Steam; there are exactly two games, Fallout and GTA, that require anything more than the world's crappiest computer to play. I have no clue about the games not represented on Steam (basically Battlefield and the Star Wars edition of Battlefield), but I bet they follow the same pattern.
The Witness has has a peak of less than 5,000 players at one time so far.
The top two games (and basically the only active "pro" games at the moment), which together have about one million players playing at any given time are both carefully tuned to run on toasters according to Valve's hardware survey.
I like Valve's current micro transaction model. You can buy cosmetic items, but that's it. I can't speak for DOTA2, but in CS:GO they don't impact the game negatively like they did with TF2. Trading from free drops also allows kids and poor people to participate in the economy, which allows them to make more money for Valve than begging mom to buy a $60 game would.
