I am sure Lindy's law is not a general law. Because i have a completely opposite example- How many years can we go by without having a passenger plane crash? as the number of years with no crash increases the chance of something going wrong increases with it. If a crash happened last week, you'd have some sort of sense that okay, it's not going to happen the week after. I can't comment on the causal mechanism, but maybe the collective of people working in the flight industry become more aware after a crash and do their job well.