If the new Gen Pythons were being built using the same tooling and machines, being hand fitted and using the same quality bluing... Then agree 100% with your speculation.
But these new Gen ones are not the same Pythons... Not even close. Completely different action, different frame, different sights, different trigger and hammer and they have ugly qr codes and SN in horrible places. They seem to be a well built revolver with Colt Python stamped on it but if you're a collector wanting a true Python and the reasons behind why it is so special... Buying one of the new ones is not going to fill that ticket.
Most people buying and collecting Pythons today for the reasons I mentioned above, especially those willing to spend the premium on them like they been... Are not going to be satisfied with putting a the new Gen in the safe and calling it a collectable Python.
These new ones are going to be bought for the most part to shoot... And shoot a bunch. No one buys a collector Python (NIB or LNIB) to take it out and go shoot it a bunch at the range.
I don't see NIB or LNIB original Pythons taking any hit outside of the drop that's already happened. Shooter grade Pythons might take a hit but they are already at $1600-2200 range anyway. The new Gen Pythons are selling for $1600+ already.
Given a choice, I bet most Python collectors would take a well cared for older shooter Python over a new Gen if both were $1600.