I'm no great expert on what is lindy and what isn't lindy. My best understanding is that it’s a relative heuristic: things which have been around longer are more likely to stay around longer. What’s more likely to be standing in 1000 years: the Pantheon or the Eiffel Tower? We know the Pantheon has already survived nearly a millennia—no wrought iron buildings have proven to be able to stand such a test of time. Therefore smart money goes with the Pantheon. If climate change or WWIII collapses global, industrial civilization, it’s unlikely there will be anyone around ensuring protective coats of paint are routinely applied.