Cold, severe winters do real damage to cable strand over decades - the wire gets brittle at the fray points faster when it goes through hard freeze-thaw cycles every year, and that's the climate band this whole area sits in. On a house built in 1944, the bottom bracket and the anchor point have usually seen eighty-plus winters of that cycle, often with surface rust nobody's ever cleaned off. Add a cable that was sized and routed for an older, heavier wood door and later reused for a lighter replacement door, and you get uneven tension that wears one cable faster than the other. That mismatch between original hardware and a newer door panel is a pattern we see a lot in homes this age - not a manufacturing defect, just decades of parts that were never matched to begin with.