The last stars will burn out in 120 trillion years

We think. We still haven’t solved things like the dark matter/energy problem. The answer to that alone could drastically change what we estimate will happen in the distant future.

Stuff only burns for so long. We might learn more about the geometry of space and that there is more out there at greater distances where maybe even other Big bangs are possible but there is a certain maximum amount of time that a star can exist.

Over the time scales of the life of a proton the maximum variability in the amount of time a star can is a rounding error against the scale of numbers needed to express the amount of time it takes for hawking radiation to reduce black holes to ultra long wavelengths of infrared radiation.

Yes, but we don’t have proof that universe can’t generate new matter. For all we know there is a mechanism in universe not yet observed that can create new matter out of little vacuum and more stars will keep forming.

So technically all we can say is, it’s likely that stars will die out in 1000 trillion years.

Yes, but we don’t have proof that universe can’t generate new matter.

True… we also don’t have proof there isn’t a tea pot orbiting our Sun since it’s creation, either.

However, there’s also a complete lack of evidence of it.

You cannot prove a negative. The evidence says no new matter can be created. No evidence that new matter gets created. Therefore, we work on the model of no new matter creation.

On these scales, the accuracy of our observations should reduce our confidence though. It doesn’t make sense to confidently say that, in 200 trillion years there will be no stars, because our observations of the rate of new matter creation (approximately zero) have a margin of error which allows for there to still be some

Until evidence shows otherwise, new matter being created doesnt fit our observations.

Go prove that wrong! Win yourself a Nobel prize in physics! That’s what science is about!