Come on, really, a 737 breaking up after an over run...wow. Which over runs are you referring to? I would be shocked if the NTSB came back and confirmed your theory. Since a 737 takes off and lands every minute why would those three over runs constitute a conspiracy?
A plane that breaks up after a hard landing or severe turbulence would be one thing, but after running off of the paved surface is another. Applying newtonian physics to the energy involved in such an accident, one would find that even an aircraft fashioned from recycled battleship steel and german tiger tanks probably wouldn't survive departing the paved surface with sufficient speed. Not trying to be too harsh....sorry.
Although, it is a good point to bring up, you don't want your overseers getting too cozy with your manufacturers.