$1800 is NOT a small amount. They couldn't sell it well enough that's why they "drop" the price which is still over priced.
When the lens was launched, the larger online vendors had trouble keeping it in stock. Admittedly, that could have been due to supply, but regardless, they had no trouble selling the lens. It's common for lens pricing to drop from the launch price after a few months or a couple of years. I expect it's part of the strategy - sell at a premium to those who are willing to pay, then drop the price to attract additional buyers. Or maybe Sigma and Tamron can't sell enough lenses, either, which is why their prices drop, sometimes more precipitously. With the Canon lens, at least, the used market value is more likely to remain high than with a 3rd party lens.
It needs IS and thus this one needs to be discontinued.
Thanks for sharing your opinion
. You are welcome to not buy the lens. In the 24-70mm focal range with the subjects I shoot with the lens, my shutter speeds are either fast enough to obviate the need for IS, or I'm shooting landscapes from a tripod. A blanket statement that the lens needs to be discontinued because it lacks image stabilization is just plain silly.