Fair enough. I wasn't trying to dictate the in-universe reason as to why NX-01 wasn't included, just theorizing.
Then again, if we're going to get REALLY technical about the legacy wall in the conference room, the depiction of the Enterprise-C is rather disproportionate to what eventually was revealed to be the Ambassador-class Enterprise-C in "Yesterday's Enterprise" (which also happens to be the episode which ends with the ship heading to Archer-4.)
ZOMFG IT'S ALL CONNECTED!!!1111