actually, screens (and projectors) have gotten much better since the old days... i'm not saying burning is still impossible, i am saying it's less likely to occur.
with respect to modern CRTs for computers, the problem is almost gone... though i am not saying burning is impossible, i am saying that the coined program "screen savers" are obsolete, and only hide screen contents today, not prevent burning of images to the screen which was a problem a long time ago.