User blog comment:RRabbit42/Birth and death dates/@comment-961279-20111007071046

I just read on the Entertainment Weekly page for info that came out of Comic-Con this year, Matt Groening said "it was always [his] intention to not have the characters on the show age, thanks to the wonders of animation." He continued with “we may do it when we run out of ideas. That may be the last sad season of The Simpsons. Bart will turn 11.”

So there you have it. Even with modern references like recent movies, TV series and guest stars like Presidents Clinton and Bush, they are for now, locked into the same ages as when the series began. To change their ages to account for the current year in our real world does not work. They are the ages they are.