I'm not sure if everyone is aware, but humanity is heading for extinction either way. My guess is that like with death most people just choose to not think about it. We don't even have to wait for the heat death of the universe. Our sun will eventually die and when that happens Earth will be shredded to tiny bits and pieces. That's about five billion years into the future, but humanity will be long extinct before that happens.

The species that is around for the longest that we know of is only about 200 million years old (Triops cancriformis). For mammals it's even less with about 130 million years, but that one is already extinct (Multituberculata).

Everything has a lifespan, including species, this planet, the sun and the universe.

But nevermind these far off events. It's been a while since I checked, but the same way the Earth moves around the sun, the sun and our entire solar system are moving, too. And based on records found if you dig deep into the Earth and analyze the dirt it seems that about every I don't remember how many thousand years we move through a part of the universe with a lot of rocks. It's called an extinction event, but humanity has barely survived it at least once. Imagine not one, but a few thousand asteroids hitting the Earth. Per hour. For a couple of weeks straight. Seems like we came up with a few names for that. Like Ragnarok, Armageddon, Apocalypse, ...