Several of the retailers do have the PDC at a heavier than normal discount, e.g. D&M Tools, where the PDC is considerably cheaper than the DRC model. (The deal referred to here is still considerably cheaper again.)
Pure speculation, however, given Festool's drive to reduce vibration in their tools due to the tightening of EU standards, it makes me wonder if the PDC is being refreshed to address vibration through the percussion mechanism? I have no knowledge what the required levels are, however, automatic vibration limiting in the new style ETS EC 150 seems to have been a major driver for it's introduction.
Even if this is so, the PDC is still a great machine (I have the DRC) with enormous power and for woodworkers only occasionally using the hammer action, no issue. For serious concrete / hard brick drilling, I would always reach for the SDS drill anyway.
As I said, pure speculation on my part……
John