I did some poking around looking for a Baltic blue on the used market . If they are around they are well hidden.
There's one on Chrono24 from a private seller without the bracelet but with some aftermarket straps:
Baltic Listing: C$794 Baltic Aquascaphe, Steel; Automatic; Condition Very good; Year 2022; Watch with original box; Watch with original
chrono24.app
Price is $794, which is hardly a bargain considering what one costs new, but I guess the scarcity means they hold value. Having a look for sold ones on the Watch Exchange Canada Subreddit, somewhere around $800-850 seems to be the going asking rate for a used one on rubber.
Considering a new one on rubber is ~$870 CAD, and the bracelet gets you to ~$990, I'd be paying the small premium and be willing to wait for a new one, myself...
WR ratings are done in a controlled environment under specific conditions. Most companies throw in an asterisk and say that their watches aren't guaranteed at the rated depth under all real world conditions. That said, I don't buy that you're getting Sea-Dweller specs from something that probably sells on Ali Express with a different brand name/dial for around $100-150.
Agreed, though I'd guess the less consistent the manufacturing, the less reliable the rating gets, as they're not testing every watch that leaves the factory floor at lower price points, even for more well-known brands. The more variable the tolerances from watch to watch, the more likely one is to get through that leaks like a sieve, hence the conservative guarantees for actual use I think. I see depth ratings like that as similar to brands like Marathon that wank a lot about being 'military grade' and 'US Army Issue'. Anyone who has actually been in the military knows that most issued gear is absolutely garbage (I wasn't, but my wife was, as were a few buddies). I still love Marathon, but it's not the sales pitch they think it is...
Not that it matters much, as nobody who is diving to even a true 100m is relying on a 100m or even 300m rated mechanical watch. My Longines Conquest is not even a dive watch, and is rated to 300m. At Longines level, I don't doubt that's accurate, but it's kind of a meaningless metric beyond knowing that should make it REALLY safe to swim or snorkel with.