Nice work on drawing up all the data. I appreciate all the effort. I'm only going to comment on one factor at the moment, which is the PS3 '14 vs PS4 '21 data. I believe PS3 holds a significant advantage for a number of reasons; Obviously no Pandemic which has affected the production of both PS4 &5, with Sony having to re-purpose and streamline PS4 production lines into PS5 production.
I'm sure backwards compatibilty plays a part but unless there are major adjustments to come for Nov/Dec sales then the first holiday of PS4 (& XBOne) post-successor release is incredibly low, a far bigger drop than any previous console afaik whether they had backward compatible features or not. Also given the shortages of the PS5 you would think it might encourage some to settle for PS4 if that's what's available.
I think the earlier lockdown high demand & the chip shortage, plus the increased cost & delays of global shipping are far & away the bigger factors in PS4 poor holiday performance, combined with it's still high price for 7y.o hardware. (the price remaining high may also be partly because of the chip shortage & shipping difficulties)