Groening couldn't even be assed to come up with character names, so he just named them after his father Homer, mom Margaret and sister Lisa. Realizing he needed to get creative on the boys name lest Brooks know something was up, he changed two letters to transform "Matt" into "Bart," which was also an anagram for brat. The fact that he thought this might throw Brooks off the scent of what he'd done either implies that Brooks is criminally retarded, or Groening has all the subtlety and subterfuge of an exploding dump truck.
So in summation: The only reason The Simpsons exists is because the creator thought that some amorphous blobs he'd created years before were much more valuable than they were; he only had maybe 15 minutes in a waiting room to come up with something new; and he's not very good under pressure. And that's how you make a classic, folks!