Agree, Best Buy is only trying to compete with online retailers, period. The price will return to a higher level for the 6D within days or weeks, guaranteed.
I feel a 6D replacement would occur after a 5D3 replacement. The only reason it wouldn't, is if the 5D line is coming to an end. If so, they'll keep the 5D3 around a couple more years, while updating other lines (kind of like what they did with the 7D).
What seems more likely is a merging of the 6D and 70D into a full frame camera geared for the crowd who uses the 70D more than half the time for video. But then again, something totally different might replace or displace all of these lines in the future, you nevahhh noo...