Yep, the only reason APS-C surfaced was outrageous, at that time, price of silicone wafers for sensors. These days with the advent of technologies this is not a real issue anymore. The only reason to go for smaller sensor nowadays would be a smaller form factor, and as we can see with recent camera bodies this is not the case for APS-S vs. FF as size wise they are virtually the same.
To bring this back ON-TOPIC
The whole package of lenses and bodies are lighter with APS-C. The 10-22 is a huge weight savings over the 17-40 and 16-35 lenses with very close to the same image quality (IMO). Combine that with a Rebel body, which is even more of a weight savings, and it is pretty significant.
I've been shooting since the early 1990's and have watched the market change over the years. There are VASTLY more people today wanting a "SLR" that is light enough to carry around all day. APS-C digital is higher quality than 35mm film these days (IMO), so people are thrilled to have such great results from such a small system.
How much do people wanna bet that 35mm was considered a passing fad and would be replaced with MF and LF again?