Do Magnaflow's wear out?

I had a dynomax ultra Flo on my daily driver jeep. I believe they have a similar design, basically a glass pack muffler but the inner tube is at an angle so the exhaust flow isn't completely straight. Mine only lasted me about 60k miles before the welds around the inlet/outlet tubes started cracking and would make a significantly louder exhaust note when the muffler was cold on start ups, and under acceleration. I welded over the cracks a few times but then my catalytic converter recently got stolen so that was my opportunity to swap it out with a new unit.