The oldest building in town survived decisions as well as weather.

Weather is only half of it. The old building is still standing because at several points people chose not to demolish it, found the money to repair it, argued for it, or simply left it alone while everything around it came down. Survival through time is a chain of human decisions, most of them unrecorded, and the structure is evidence of all of them.

When something has lasted, ask who protected it and at what point it nearly went. The answer is usually more interesting than the architecture. This applies to institutions, friendships, and practices as much as to buildings.