Why do you consider it an issue?
Let me put it this way: if the costs of buying a Mac is too much, you certainly can’t afford the developer that needs to use that Mac. The cost of the hardware is such a tiny part of the total cost of developing an app that it’s laughable to consider it a major obstacle.
What is arbitrary about it? Porting the iOS developer tools to Windows would be an enormous amount of work with little benefit.
Developer time is expensive, hardware is cheap.