Again, I'm not at all arguing for a complete absence of mutual cultural influence or of borrowing or even dialectical relationships between Christian (and Jewish) and pagan festivities in instances throughout the history of the West, only that there is no evidence of *direct* borrowing or influence when it comes to the origins of Christmas. And what makes that remarkable and interesting is how much direct evidence we have of other instances when dates of pagan festivities were directly used by Christians in order to repudiate the pagan rituals (especially the imperial cult). (I am of course using the term "pagan" not pejoratively but in its typical historical use.)
I would say we have to be cautious about identifying intentions of ancient cultures and peoples ("they must have known") when it comes to something like this without evidence. McGowan addresses the point I'm making regarding cultural influence and lack of evidence here:
"Granted, Christian belief and practice were not formed in isolation. Many early elements of Christian worship—including eucharistic meals, meals honoring martyrs and much early Christian funerary art—would have been quite comprehensible to pagan observers. Yet, in the first few centuries C.E., the persecuted Christian minority was greatly concerned with distancing itself from the larger, public pagan religious observances, such as sacrifices, games and holidays. This was still true as late as the violent persecutions of the Christians conducted by the Roman emperor Diocletian between 303 and 312 C.E.
"This would change only after Constantine converted to Christianity. From the mid-fourth century on, we do find Christians deliberately adapting and Christianizing pagan festivals. A famous proponent of this practice was Pope Gregory the Great, who, in a letter written in 601 C.E. to a Christian missionary in Britain, recommended that local pagan temples not be destroyed but be converted into churches, and that pagan festivals be celebrated as feasts of Christian martyrs. At this late point, Christmas may well have acquired some pagan trappings. But we don’t have evidence of Christians adopting pagan festivals in the third century, at which point dates for Christmas were established. Thus, it seems unlikely that the date was simply selected to correspond with pagan solar festivals."
I understand the impetus behind what you're saying—though I wouldn't conclude there was ever or would have been reason for an attempt to "emulate" pagan festivals or rites by Christians—but I'm hesitant to draw the conclusion you do because there isn't real evidence there.
"In music I think it's very, very dangerous if you start to compare and say, 'This is good, this is not good, this is only one possibility' . . . there are so many possibilities, but what is important is to be open to that." - Pavel Steidl