Like with iOS, it's not just a question of market share, but of revenue share.

Questions to ask when deciding what platforms to support:

Of Android and iOS, which has the users willing to spend money on apps? More than $0.99?

Of Windows, Linux, and macOS, which has the users willing to spend money on apps? More than a few dollars?

In the USA it's 13.5%, and I'm willing to bet that in urban US areas it's even much higher. Here in London (UK) it has to be at least 20%-30%.

But yeah, not everyone's using Macs. It's the biggest vendor, but there are more non-Macs than Macs.

Another distinction to make is business vs private users. Unless something has changed recently, Macs are basically unheard of in offices (aside from maybe the receptionist), so if 50% of the market is businesses where there's 0% market share, "how many people use a Mac at the coffee shop" will overstate their overall market share by 50%.

I not sure about the office bit though. In my office there are some macs although they are a minority. I'm also not sure offices account for 50% of the computers.

But yeah, many other variables to consider. Age as well, it's mostly younger people in coffee shops.

Everyone at our company who isn't a developer is on a Mac...