The teal shift is probably not from aging. It's just a trend. They probably wanted to do a quick colour-pass to make it look "nicer" for Blu Ray, maybe pop the colours, get rid of any pink shift, etc. So in these cases it's usually up to the discretion of the colourist, and colourist sort of automatically go for the teal-and-orange look nowadays because the older pink-and-blue look is dated. If you saw the film on its own you'd probably hardly be aware it had been changed, other than something was different, it's the side-by-side where things seem more noticeable. TPM seems to have had a colour-pass too, but the colourist kept things more neutral--actually, he seems to have preferred a more "golden" cast overall. ROTS looks about the same to me, but maybe because it was the most recent.