Hi, you are right. Text rendering on old displays is really bad and icloud with use of Helvetica Neue type is especially eye kicking. My guess is that people with old displays will go to apple store one day and suddenly realize how beautiful the icloud looks on retina displays (say macbook pro). In such an occasion customer feel another argument why buy a new retina capable mac and why to hate his own old computer.
Just for comparison, that's what I have to face daily on my old NEC monitor (via Chrome, win 8)
The top arches from n, m, b, e and s are one pixel higher than top finish of u and r strokes. That result in „jumping“ while reading which is very unpleasant depending on one's expectation of typographic quality.