I'm sure you kept up on the tune. Most Cobra owners are guys who haven't seen a carburetor before or haven't touched one in decades...
That also jives with the point I was trying to make. An engine that's tired at 100k miles isn't what we're used to seeing these days. My Explorer has 185000 on it and with the exception of a valve cover leak, doesn't lose any
oil. My '90 Mustang LX 5.0 had about 110k on it and when I pulled the heads to bolt on a set of GT40's, the crosshatch was still very evident, along with no cylinder ridge.
Carburetors are certainly easier to mess with, but I do think they contribute to accelerated cylinder wear. Just harder to keep up on the tune, along with keeping a constant ideal A/F ratio.