Plummet, what are you talking about? At least one (maybe) was offered by Jomashop at decent discount, now a 6 to 10 week wait which in New Yawk terms means "fuggedaboutit ", it ain't happening. There are no great deals on Chrono24, all above retail and the number is relatively small, <0.5% of the total. None available to walk-ins at OBs or ADs, it's way oversubscribed at retail price. It's sold out. Prices are not plummeting. Will it hold it's value, no one knows, but I see no reason for any hand wringing.
Whether you can get hangtags, outer cardboard box, coffin is a hit or miss affair and can vary by retailer and location. I bought a plain hesalite Speedmaster two years ago in the Geneva boutique and they were just going to throw the brown cardboard box away so I salvaged that, then when I got back to the hotel I discovered the hangtag was missing. Walked back to the boutique where the salesman reached into the trash can and retrieved it, so they aren't sacred in Switzerland. But other places will almost arm wrestle you for the hangtag saying it is 'verboten' to give it to you. Usually for watches in dealer stock the outer cardboard box and coffin are long gone. But it's an interesting game with these associated items that have no real value but which the collector likes to have for completeness..