Eternal present vs. impermanence

When I wrote about students dreaming of a stress-free time that would never come, I suggested that there might be some healthy value in recognizing that the current stress would not last forever. Kenny disagreed:

"But Eckhart Tolle would, of course, completely dis- agree with your suggestion
that "It's probably a healthy way to deal with stress" and right now I'm
inclined to agree with him. Believing it will end soon is precisely what enables
you to sustain it indefinitely--right up to retirement or beyond--without really
confronting what it's telling you, and changing something."

Two prime truths of Eastern thought seem to be in conflict. On the one hand, if you pay attention to the moment, you are released from the tyrrany of past and future. On the other hand, if you recognize the impermanence of the current situation, you are liberated from the compulsions and reactions to the present moment, and are capable of detachment: "This, too, shall pass" was one of S.N. Goenka's favorite teaching phrases.

I have been meditation on this seeming contradiction, and ran out of time (ironically) to say any more about it now. I am guessing that it is only an apparent contradiction, but it's going to take a little longer for me to find the right way to express it.