It's evident that the Mk I will be discontinued at some point soon. The replacement is several hundred dollars more expensive, even compared to MSRP. But soon, you won't be able to get a new 24-70/2.8 cheaper than the street price of the MkII.
Um, are you really suggesting that at some point the Mk1 will cost the same, or even more, than the $2300 Mk2, purely based on supply-demand economics? That is so unlikely as to actually be preposterous.
I think you misinterpret. What I mean is that soon the original will be discontinued, and retail stock will dry up, and at that point, street price of the MkII will be the only
option for a new 24-70/2.8 lens (from Canon, of course), i.e. the MkII. That fact is what's going to drive up demand for the current 24-70. Here's what I mean:
During the last non-rebate period (most of 2011), the average list price of the lens was just under $1400. It's worth noting the Canon states
the estimated retail price of the lens as $1399, and most of the retailers sold at or a bit under that price. Look at B&H or Adorama today - some retailers with the lens in stock are selling it for $1599, $200 above
Canon's estimated retail price for the lens. Why are they selling it for more than the 'usual' street price? Supply is low, and demand is high for the reasons mentioned above. There are still a couple of retailers with the lens in stock selling it at $1399, J&R and Sears, for example, and a lot more retailers listing it at $1399 but with no lenses to sell at that price.
This is exactly what happened with the 70-200mm f/2.8 IS at the time the MkII was announced/released.