Some very good points there, especially the one about market demand. Tamron & Sigma do have something in this price range though (that sell extremely well), and that is their 17-50 f/2.8 zooms
, the least expensive of which costs a whopping $680 less than the Canon 17-55 IS (B&H prices, not including the rebates running on both at the moment). Granted, the $440 Tamron doesn't have IS but for an extra $170 they'll give it to you.
I agree that maybe there's not enough room in the stable for my proposed "cheap wide prime replacement kit zoom" (& I'm certainly not suggesting a revival of the 20-35 USM
), but it looks to me like Tamron & Sigma have a better answer to replace Canon's aging non-L wide prime lineup than Canon does.
If they wanted to do something about that then I think something like a hypothetical 18-45 f/2.8-3.5 IS with the same cost-cutting measures I mentioned above (built like the kit zooms) and the same size & less weight than the non-VC Tamron would do very well if priced right (i.e. significantly cheaper than the aforementioned Tamron), and I don't think it would cannibalize the sales of the existing 17-55 version based on its range & aperture and "pro" features like better build quality, non-rotating front element, etc etc. as anyone in this price range is going to buy the Tamron or Sigma, not the 17-55 f/2.8 IS.
Don't get me wrong, I'm not saying that I'd personally rush right out & get one of these if they made them, but Tamron & Sigma have clearly demonstrated that there's a large market for reasonably-priced fast standard zooms for crop cameras, & are currently eating Canon's lunch in this particular segment.