What is the point if humans exist another 1000 years? Or does it have to be a million years? How many years does it need to breed meaning?

Enough that we can spread humanity into space and/or develop sentient technology.

Forever. I mean, life is a natural consequence of the nature and physics of the universe, and human civilization is a natural consequence of life processes. Existence and progression is the meaning.

> Forever.

Already failed then.

Scenario 1) The universe will end in heat death, the big rip, or other similar cosmic catastrophe.

Scenario 2) The universe continues on for infinity, giving plenty of time for even the most ridiculously unlikely of events to occur. It is therefore inevitable that humanity or whatever progeny it might have will still ultimately cease to exist.

Scenario 2 isn't actually so clear. Over time, humanity can decrease its suceptability to being wiped out by unlikely events at a faster rate then the events themselves over time.

But we can never hit 0, and infinity is a long time.

That's leaving aside that 2 is already pretty unlikely given what we know of the universe.

Time is a property of the universe.