The better question is, why are bolt actions still so popular today? Sure they can be made cheap, but they are bulky, ugly, and only marginally faster than a break action single shot. Sure, you can learn to run a bolt action well, but put that same time into a lever, or pump, or just about anything else, and you will be running circles around a bolt. About the only legitimate advantage a bolt still holds is that they are easy to make a one piece stock for, and can be made fantastically accurate.
Reliability? I don't know what bolts you guys have used, but generally I find bolt actions to be about the LEAST reliable guns out there. Especially the dirt cheap ones. Sure a Winchester model 70 is well proven, but there is a whole heap of bolt actions that are not. And bolt action shotguns? They are the worst of the worst.
Rant over.