Well yes, as you say, that's the easy way. And (before I start my obligatory scoffing) I admit, there's a lot to be said for taking the easy way out (otherwise there wouldn't be a song about it).
And obviously there's something wonderfully elegant about a disk brake system where you can substitute any wheel set with approximately the same overall diameter.
Indeed, if the fatness of the tires is the only variable that has any effect on ride quality, you'll be in luck, because that'll be the only variable you'll experience.
So, as I say, this approach has a lot to recommend it.

On the other hand, disk brakes require heavy and more or less inflexible fork blades that (some experts argue) have a detrimental effect on ride quality. Now if you spend your whole ride worrying about whether your brakes are up to the task of stopping you, then the awesomeness of disk brakes is worth any cost.
I, however, am one of those guys who spends a lot of time pedaling and very little time braking, and it seems to me my brakes don't have to be awesome. They only have to be good enough. And rim brakes are good enough for me. They allow a lighter frame and more resiliant fork blades... And that seems more important to me than braking awesomeness.
At least in theory.