Exactly. As a developer, what I decide to build depends in part on the market "out there" and in part on what tools I have. When I had an early Mac, I talked my office into using more Macs (despite a corporate "Windows only" directive) by using my own Mac at work (I bought it myself) and building some useful things with it that others wanted to use.
When I switched to Windows, I learned Visual Studio and C# and built several customized tools that coworkers could only use on Windows. I also recommended Windows machines to family and friends, who almost all went with my recommendation.
When OSX came out, I and many other developers switched to it. Finally, a serious OS from Apple. When we did, we pulled lots of families and friends with us, and we made a lot more things (open source installers, for example) available for Mac users.
If Apple succeeds at restricting Macs to people who want lightweight, fashionable, "Apple lifestyle" accessories and need confusing things like folder hierarchies removed from the OS, many of us will move again and take those IT decisions we influence with us.
If I get off the Mac, for example, I will quickly forget how to do things I need to do to provide tech support to Mac-using family and friends, so I'll probably begin recommending Chromebooks to many of them, shifting some of my support away from their individual machines and onto web portals and web apps I build for them on my own servers.
And I went with iPhone because I was a Mac user, and I figured I would get some benefits from using the two together, which I did. If I'm no longer a Mac user, those benefits vanish, and I'll probably switch to an Android phone with an audio plug. (Maybe we developers are just a vocal minority, but we'll probably get pretty vocal to others about why we're leaving Apple if we do.)