Even if the universe were eternal, the way I see it eternity is just another kind of ending. I think the important thing to realize is that a thing does not cease to have value simply because it is impermanent.
It can value itself. After all, that's what it's doing now via us. It doesn't necessarily have to configure itself into something like a human to perceive and appreciate itself.
Is the noise truly random, or is it just unpredictable? Does the maximization of entropy indicate no deviations from equilibrium will spontaneously occur? Does the lack of memory indicate a lack of consciousness?
We can value whatever, but eventually there won't be anyone left to do the valuing. Impermanence doesn't stop us from valuing, but impermanence does guarantee that value won't last. Which may or may not bother us now, depending on how existentially grumpy we feel in the moment. But luckily, those feelings are impermanent as well.
All true, but of course the point of the idea we're discussing here is that there may not be any reason to assign special weight to the value of things in the present or the future, over the value of things in the past.