Although the new lenses 24, 28, 35mm IS are great, are not as light and cheap as can be EF-S lenses.
What makes you think that a "quality" EF-S lens will be light and cheap? The 17-55 isn't light like the 18-55 and when I bought it, it was around $1000. Not sure I'd call that cheap, but I do agree that the quality is much improved over the 18-55 that came with my camera. I also really like my EF-S 60mm.
IMO, I think that if there is a superior lens out there, people will buy it whether or not it's EF or EF-S (assuming the camera is a crop camera). If canon made high-end EF-S lenses, then they would sell them and make money. If better quality is desired as one's skills progress, then canon can get even more $$ out of you as you move up to full frame and EF lenses. I believe the money is in the glass, not the camera, for the general public, and if canon made high-end EF-S lenses, they would make money off of them. There is a natural desire for people to get better/faster/smarter products - why not add a rung to that ladder and make some additional money along the way.
That is my opinion of course.