What is your point?
Only that even in other parts of the world, the Canon lens is available for substantially lower than the MRSP when it is purchased as part of a kit. So even in other parts of the world, the Canon lens is available for much less cash, as part of a kit, or used as the case may be.
I live in India and the Canon 24-105 can be purchased for local currency that is about equivalent to $ 900 - A used lens can be had for as less as $ 650. So what I was implying was that the Canon lens is available in other countries as a cheaper price too. Sigma will be priced above the Canon lens (when it is released here) - I doubt too many will buy it over the Canon lens.
I guess it is pretty much the same all over. but then, maybe in your country it may be different.
PS: Photography gear in India attracts customs duty of 30%, so @ $ 900 the lens is a bargain.
PPS: English is not my native language and I sometimes have difficulty getting my point across.
Cheers ... J.R.