Yes, it is true that once you remove the sticker, cut the chain, and put it on your wrist, the value of the watch drops. Only few watches can be taken as an investment, like Rolex ,PP or maybe Lange. But for a watch to increase in value, it takes decades, normally after the watch is discontinued. Example like Rolex 1680, it is selling at an average price of $15k USD now, and the PP 5970, selling at a phenomenal price that can even reach $400k USD. If you buy a brand new watch, it is less likely to be taken as an investment, most people take it as a hobby and appreciates the watch, and to pass down to the next generation. Otherwise, it is also easier to sell and not lose too much in order to upgrade into something better. Different watches hold different value, not all watches can be taken as an investment. Anyway, thinking about the resell value of a watch when buying it is just like thinking about divorce before marrying. Only think about investing in a watch when you have the ability to.
Correct me if I'm wrong. Cheers