This isn't a generic wear-and-tear story. Green Bay sits in a severe cold climate band, and a huge share of the housing here - built between 1962 and 2008, with the bulk of that from the 1980s and 90s - was fitted with doors and hardware sized for the building codes and materials of those decades, not for the insulation standards or steel gauges used now. A single-layer steel door that was perfectly adequate in 1985 simply wasn't engineered against the freeze-thaw cycling and sustained cold we get through a full winter here.
Across the service area - 68,143 households, 35,524 of them owner-occupied houses - that means a large, aging, mostly original population of doors reaching the point where the foam core has shrunk away from the skin, or the track has warped slightly from decades of condensation and thaw at the base. It's not that these doors were built badly. It's that they were built for a different set of expectations, and three or four decades of our winters are exactly the stress test that exposes it. That's the local reason installation calls cluster around certain house ages rather than coming in evenly from everywhere.