It's far less about being a better writer. For starters, they are from an affluent suburban community. Like my parents always said, "It takes money to make money." Second, they have a certain uniqueness (albeit sucky uniqueness) about them that gives them the ability to engage anti-label immature kids. Thirdly, it's that demographic of immature kids that will pay for the flavor of the month music. Most (and I don't say all as there are probably some intelligent musicians/listeners out there somewhere who enjoy this) buyers into this joke of a band do it for reasons far beyond the actual music (the look, the "en vogue" stupid auto-tune, etc.). Fall Out Boy actually made some decent music at first. Nothing amazing but it was interesting tongue-in-cheek stuff.
Most importantly, it's all about who you know. The reason many of us don't make it big like this puss-party band is because we A.) Let our life get in the way of our passion and don't engage the producers and consumers who can get us ahead and B.) weren't born with the silver spoon in our mouth, having Billy Ray Cyrus as a father or living next to the bigshot record producer in suburbia.