The premium Chinese tourbillion watches are not cheap, much more expensive than silver collector coins so the investment is quite substantial.
Tourbillon watches are supposedly expensive because they are suppose to be difficult to hand made and therefore exclusive. If the Chinese are able to mass produce these watches and sell them like $300-$500, it will undoubtedly depress the prices of such watches in the long run, except for probably the very expensive tourbillion sold by likes of Patek philipp where the brand itself is worth a lot of money. What is there to stop manufacturers from flooding the market?