I own two 'classic' air-cooled Porsches - a 1987 911 and a 1995 911. I get where you're going with the Porsche analogy, but it's not really a good one. The early Porsches were completely different cars - totally different appearance, a much more raw, visceral driving experience (no driver aids, no power steering, little to no sound insulation, simple interiors with bare bones dashes, etc. etc.) The newer water-cooled cars starting with the 996 in 1999 were 'ugly' in the eyes of the Porsche faithful (me included), and sported many 'improvements' that were only there to meet stricter noise/emissions standards and had nothing to do with improving the driving experience. Couple that with less than sound engineering on the normally aspirated 996/997 engines (Google 'IMS Issue' or 'RMS Issue' if you're interested in the gory details) and you'll get more evidence as to why the earlier cars are more desirable.
The 127/372 comparison is entirely different. I haven't seen the 372 in the flesh, but photos and other information I've read lead me to believe that it has virtually the same appearance as the 127, and is possibly more historically correct. The 372 has an in-house movement which is typically seen by watch collectors as an improvement over an ETA movement like that used in the 127. The 127 isn't really an 'historical' watch in the sense that it is a reissue of a historical watch that contained an outsourced movement (albeit a Special Edition that was produced in small numbers). Early Porsches are the real deal, the originals.
I'm certainly not putting down the 127 in any way. I think it is a terrific watch and I'd love to own one. But with the introduction of the 372, basically the same watch in terms of appearance but sporting an in-house movement rather than a more generic, outsourced movement and obtainable for about 1/2 the price of the 127, I see it as a pretty attractive alternative. Which leads back to my original post about being surprised it hasn't caused values of the 127 to significantly drop. But apparently the Panerai community currently values the rarity and soul of the 127 more. I wonder if time will tell a different story.