I don't think they really care about "keeping up" and don't think they should be expected to. Brand New isn't one of the thousands of scene bands that are just trying to break through, they've been there. they're at the top. They set the standard, they don't need to churn out material to stay relevant they're fan base will be there when the new album comes even if it takes 5 years. Kind of like how Yellowcard took a 3 year hiatus and came back strong, and they were actually officially on hiatus and not even touring. The big bands that have been around for awhile and have made a name for themselves don't need to put out an album for the sake of putting out an album
At an average of four songs a year, I kind of feel they do need to keep up. In entertainment, sometimes your only as good as your last release. And I don't consider artists like Brian Fallon, Dallas Green and Andy Hull to name a few as scenesters. They work hard, write good music, and tour, and so on. I love Brand New, but I can not say for certain that in three years following the release of Daisy they'll have another new album anywhere close to ready. I makes me sad to say that.