I have a Custom Colt 1911 Light Weight Commando and I doubt if I ever see it wear out regarding the frame. I like the steel frame guns myself. But regarding your question about alloy frames. It brings to mind all the rounds and abuse the Beretta M-9 Military Pistols take. Never seems to be a significant problem with the Alloy Frame, at least I have never heard of it. So I doubt if you and I would ever see it no matter how many rounds we shoot. And I know some (Frames) of them had more than 30,000 + rounds through them on the low side. So i guess who knows how many rounds it would take to wear one out. Also would obvioulsy depend on the loads and other effects.
The Constitution is not an instrument for the Government to restrain the people. It is an instrument for the people to restrain the Government!
“Americans have the right and advantage of being armed. Unlike the people of other countries, whose leaders are afraid to trust them with arms.”
James Madison. Author of the 2nd Amendment