They (Apple) most likely use PCs and Altium, OrCAD, or something of that type. Given the tight integration with the enclosures in many Apple products I would think that Altium is the best fit.
Most professionals aren't into the entire 'fan boy' attitude. You use whatever is the best tool for the job. Apple doesn't even go after the workstation market from what I've seen outside the graphics/video/content creation fields.
In an example of what I mean, for a very long time www.micosoft.com was hosted on Linux servers. It wasn't moved to Windows servers until they developed a web server OS that didn't suck (it took them awhile).
For hobby use Eagle and DipTrace should be sufficient and run on Macs.
You can always just boot up a Windows VM and use whatever you want. Also, although Altium doesn't work all that well, it uses Direct3D for rendering and VM performance isn't all that great yet. I am not sure if OrCAD is using any 3D rendering nowadays.