You basically only know one thing about something, which is how long it has been around. The things that come to life and die that you observe will be, on average, in the middle of their life.
So if something has been around for five years, given no more information, your best bet is that it'll be around for another five years.
One year? Another one year.
Hopefully this explains well why the Lindy effect also says that something that's been around for a shorter period of time is more likely to disappear sooner.