When it comes to watches, for the major brands - especially Rolex - the name is worth a significant part of the price. Rolex are a very secretive company (more so then any of the others - they are privately held by a trust - and publish almost nothing about their operations). But I have seen a number of estimates that suggest that their production costs are likely no more than 20% of retail. A huge amount of money is spent on advertising and brand promotion.
There are quite a few videos of people taking fake Rolexes in to be verified by specialist dealers. The efforts that are made by the fakers is quite remarkable. There are tells. But the fakers get better and better. A cheap knockoff won’t even weigh the same. But high quality knockoffs would fool anyone who didn’t know exactly what to look for. And still hard if you didn’t have a real one with you to make direct comparisons with. Often only very slight differences in the quality of finishing steps. Slightly less distinct engraving, tiny burrs on edges only visible with significant magnification, and so on.
Take the back off and it is more obvious - but even here better fakes take the time to attempt to put Rolex branding on the movement. But it is a lot harder to make the movement look right. The fakers don’t make movements, and Rolex movements, whilst largely machine made and finished, are made and finished to a very high standard. But just the layout of the movement is an instant giveaway.
The very high price of Swiss watches partly reflect the high cost of doing business. The ability of the Chinese manufacturers to make high quality watches cannot be underrated. Right now for a watch to say “Swiss Made” only 60% of the input has to be from Switzerland. It is becoming more common for the other 40% to be Chinese components. Which can easily include cases, dials, hands, bracelets, crowns - all the externally visible bits. Traditionally most Swiss watches were assembled from parts made by specialist parts manufacturers that serviced the entire industry. Rolex being one of the few mainstream high volume brands that does everything in house. Large conglomerates like the Swatch Group, LMVH, or Richemont, (who between them own nearly every other Swiss watch brand you have ever heard of, from the cheapest to the eye wateringly expensive) own many companies and can source internally, but for their cheaper and mid-range watches almost certainly use many Chinese parts.
But as more work is outsourced to China, the capability of the Chinese parts manufacturers has risen, and now they can make anything to as high a quality as you want to pay for. So fakes have risen to a similar level.
The advent of micro-brands - which design a watch and then source all the parts - sees watches at many price points and qualities. The parts manufacturers will cheerfully finish the parts to whatever quality you want and are willing to pay for. To the point where the same part might appear on different brand watches at very different price points, but with noticeable differences in apparent quality.
Movements are where the fakers become stymied. Movements are not trivial to design, or set up to manufacture. Movements generally in use go back a long way, and many have a common heritage in design. The vast majority of Swiss watches have movements based only a few original designs. Fakers can only use a few movements, and all are from this heritage. Faking a real modern Rolex movement would involve investments that make no sense. Nobody buying a fake would care anyway. Only someone being sold one as real will care, and the fake manufacturers are not in that game.
Cartier make a problem for themselves in that they have a lot of models with quartz movements. And everything is about the brand and design. So they are a really easy target for fakes of any quality.