The Wii can run the Opera web browser. The Xbox runs a modified version of Windows 2000. Are the Wii and the Xbox personal computers?
A Mac—or, as I prefer, Macintosh—is a personal computer made by Apple. Yes, the iPhone runs a modified version of OS X; but a Dell computer can run a modified version of OS X too (see the OSx86 project). Neither are Macs.
In Mr Howard's scenario the iPhone replaces every function of the Macintosh. The iPhone 4s envisioned would not be Macs, though they might herald the end of the Mac. : - /
For the record, I just burned an iTunes-purchased, DRM-protected album to a CD-RW. Using iTunes on an 'unauthorised' computer, I then imported the album as DRM-free mp4 files. Voilà.
Which shows that it is easy (and inexpensive: I can just keep using the same CD-RW) to back up one's iTunes Store purchases. It also shows that DRM is stupid. In ten minutes' time I can convert DRM-protected files into unprotected files, so DRM turns out to be more of an inconvenience than real protection against unauthorised reproduction of music.
Take hope. The future is DRM-free.
Everyone Uses a Mac Nowadays
Do You Really Own Your Music?