That has not been my experience, at least with Apple laptops. Even when rated for 1000 cycles, I'll get the warning that service is needed (AFAIK that means 80% capacity or lower) well before then. I've seen this on several, but the one I just checked is at just under 670 cycles and has had that warning up for some months already.

Maybe iPhones are better about this, though, I don't know. But I definitely don't have a lot of faith in the laptops maintaining 80% for 1000 cycles.