Proofs of security

Has anyone done any research into how much better new cryptosystems with proofs of security do, as opposed to their unproven cousins? It seems that having a proof of security doesn't actually improve the odds that a system will survive attacks. But thats my intuition, not a proven fact. ;) Has anyone read a stack of papers and done some statistics? -- "It is seldom that liberty of any kind is lost all at once." -Hume