Yup, that's exactly the idea with massed fire. If you can't hit a point target, just designate it an area target and get enough rounds together to be effective on the entire area. When it comes to taking down a blimp with a round that barely has the energy to get there, though, I imagine that number of rounds is measured in thousands at least. Less of "keep firing" and more of "we're gonna need a lot of guys".
And also don't forget the numbers I'm using suggest this is only plausible if you're firing more or less straight up, meaning the area you're ultimately targeting is where you are.
