I think the reason is that they inceased the size of the windows on their subsequent designs. Just compare the glass area on a 757 with a 737. Having the eyebrow windows just became redunant and another peice of equiptment to maintain, with the extra visability from the bigger windows
This isn't anything offical. I just base this on the size of the windows.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.