Or not. It only doesn't happen, because of the status quo. Most futures end with Lisa married to Millhouse in the same way that Arnold/Helga was going to happen had Hey Arnold been allowed to continue. In fact, since Craig based Arnold on himself as a kid on top of voicing Helga's own wheezing creeper Brainy and his wife came up with Helga's stalker crush, one could say that Craig Bartlett's marriage to Lisa Groening IS a real-life Millhouse/Lisa (Matt Groening did based the nuclear Simpson family on his own) or Arnold/Helga/Brainy.
I hate Milhouse. I love Bart. That's it. I ignore Milhouse instead of flaming at his fans because i'm a good guy and i respect it. If you don't like Bart,and Bart and Lisa's friendship (watch "Milhouse doesn't live here anymore" and you will understand me) ignore me,all the fans,and it. Have a nice day!
Look, I like Bart too. He and Millhouse are best friends, if you've forgotten. Also, I do like Bart and Lisa's sibling bond, but unlike some, I am also able to distinguish between sibling love and incest (to that end, I don't understand people pairing Bart and Lisa, since they're siblings) and though I support the former (sibling love), the latter (incest) I view as immorally wrong. I just feel for Millhouse, since he's the butt monkey (much like Meg on Family Guy).