Being Mac only can be an advantage - I’ve been on both sides of trying to maintain & use non-trivial dev environments and the more OSes you bring in for people to work on, the harder it gets.
Bringing in Windows or Linux has a set up cost and a maintenance cost that may exclude it from even being considered.
Edit: plus, Macs are ARM, other options are inevitably x86. So it’s also two CPU architectures to maintain support for, on top of OS specific quirks - and even if you use eg Docker, you still have a lot of OS specific quirks in play :/
Bringing in Windows or Linux has a set up cost and a maintenance cost that may exclude it from even being considered.
Edit: plus, Macs are ARM, other options are inevitably x86. So it’s also two CPU architectures to maintain support for, on top of OS specific quirks - and even if you use eg Docker, you still have a lot of OS specific quirks in play :/