Since time is money, and setting up, troubleshooting and properly maintaining a PC takes much more time, this makes sense.
When me and my relatives used Windows, I was constantly fixing, formatting, reinstalling, uninstalling, cleaning, tweaking, and troubleshooting everyone's computers. A badly maintained PC will slow down within mere months, and the vast majority of people who use them have no idea how to maintain them properly. And a slow PC costs money, because money = time especially for a corporation.
Ever since I convinced everyone I know to get a Mac (for my own benefit), I haven't been called to fix anything. No one had to reinstall their OS and all their apps, no one had to go into the Registry Editor and change obscure keys to make the PC run again, no one had to go into msconfig and turn off processes that should have been removed when an app was uninstalled, etc.
Windows is absolutely fine for people who know what they're doing and have time and are willing to mess around with this sort of stuff. But for those, including myself, who'd rather spend as little time as they can at a desk in front of a computer, the Mac is definitely going to save them a lot of effort, time and money.
When something works well, you don't even notice it.
This is why it's important that Apple should continue to take the Mac seriously. It's something they're consistently doing well, and that the world needs rather than just wants. The iPhone is great and all, but it's not nearly as important as a real computer to get your work done. And the iPad isn't going to replace anyone's PC anytime soon.