Unless you stick with MS dev tools like Visual Studio and .NET, unfortunately, I'd have to say yes.

You can still use Windows for general software development, many people do, but most tutorials and tools are aimed at unix compatible systems. Also, when it comes time to deploy a server on AWS (or any cloud provider other than Azure), it'll help to know your way around a unix-like OS.

Also consider that for iOS development you need a Mac, and those seem more lucrative these days than Windows apps.