Let's be honest about it, I doubt almost anything sold on selly telly will ever reach heirloom status, bar perhaps some of the jewelry that is of genuine quality and some of the higher end collectibles. I completely agree with you, in reality many of the products they sell are perfectly good for the price you pay. It's the utter tripe they spill with their sales pitches that spoils it, coupled with the faux over-reaction to products that are anything but unique or ground-breaking.
Yeah, I'm not sure about jewelry, not seen what they sell or if they do many shows, think i've seen one show, certainly not as regular as the watch show that's for sure.
As to the watches, I suppose there is a few that could become heirlooms as in passed down, having sentimental value, rather than any monetary value, but those would be very few, i would say about 99% of IW watches are throw away watches, ie when they're broke, they're broke, it's not economically worth it to get them repaired or serviced. In 10 years time, if say one of your Swan & Edgar (that could be Heritor, Reign, Earnshaw, C.Weisz, DeLorean or any of the funny brands) watches was needing serviced, it would be cheaper to buy a new watch than service/repair, and despite IW claims about insuring, even if you kept that Swan & Edgar etc in a box and never wore it, you'd be lucky if you could sell it for a tenner on ebay.
There are a few that may be of interest to watch collectors many years from now, but not that they would be any kind of investment for you, but folks would pay a few quid for them, nothing like the price you paid though. They need to be something, as you say unique, have some kind of heritage, and actual history behind them, naming your watch brand after an old dept store, or saying they are designed on the banks of the Rhine, or after a famous car from the past, and getting the Chinese to make a couple of hundred of a watch to claim Limited edition, with generic Chinese movements in them, doesn't count though. Hundreds of no heritage, no history type brands out there doing exactly that, so it's nothing unique or special, fine for folks just wanting a watch for today, but not something you'd buy for passing down or as an investment etc.
I would say from what I've seen, watches that would probably interest collectors in years from now, would be one or two Vostok Europe, those with the Vostok movements in them, the rest, although well engineered all have pretty basic Seiko or Citizen movements in them. nothing unique or special. One or two of the Sturmanskies, Mathey-Tissot and maybe the Buran, but from the rest can't think of anything special off the top of my head, sure there's more that would interest watch enthusiasts today, but more than likely those watches wouldn't be of much interest to watch collectors way down the line in the future. But us humans are a funny breed, who knows maybe in 50 years time, there will be craze and collectors desperate to get their hands on a vintage Swan & Edgar watch
or maybe not.