I wonder why would development of such lenses stop, as it would imply lens developers at Canon are either doing nothing or were fired, then rehired several months after that.
Perhaps you were unaware that the earthquake in Japan damaged the plants where R&D was done, and power outages made it impossible to work even in undamaged plants. Once structural inspections and repairs were completed, there was still power outages. All production ceased at the affected plants, and that included R&D.
Once power was restored, I suspect that emphasis was given to getting the production line started again. all those optical instruments had to be inspected and re-aligned, and the furnaces where the lens blanks are made stabilized, it is suprising that they are back in production so soon.