We love to blame corporations (I'm hardly an exception) but here blue collar folks are also to blame to an extent. The military industrial complex also provides many jobs and no representative wants to be the one who has the military hardware factory in his district shut down and lay off a bunch of people because that hardware isn't necessary. So they'll all fight tooth and nail to maintain production even if its not necessary to keep those blue collar manufacturing jobs in his district instead of having them laid off and vote against him.