Would be interesting. My money may go towards the auto simply functioning with less maintenance (depending on the gun). Overall lifespan, I dont know. people used to be worried about plastic framed guns holding up. Todd Green did this particular test with a G17, the part with wear that stopped it was the breech face of the slide. Interesting if you havent read it.
http://pistol-training.com/archives/6885
Smiths seem to need a hand now and then in centerfire calibers. My old k22 has well over 200K rounds through it best i can recall, and hasnt ever had any internals replaced. LSP 972, who passed recently, had a couple or so Smiths that had obscene numbers of rounds shot through them when he was shooting competition. I dont recall all his comments and observations about revovlers in general. he truly liked them and was very well experienced working on them as well as shooting them. I believe theres a few other guys here that have also shot truckloads of rounds through revolvers. Wayne perhaps being one, I dont recall the others who had shot them a lot over time and in competition.