When people buy a Patek the cost of the gold is just a little fraction of the watch.
Even when speaking about the cheapest Patek you still have to pay more or less 13.000 euro for a simple Calatrava. How much gold does a calatrava use ? 60 grams ? It won't be much more. Gold is at 30 euro per gram today so the basic material price is 1800 euro. So even if the price goes up 30% is would be 540 euro more expensive
Well, if the calatrava would go up from 13.000 to 13.540, nobody would cancel his order because it became too expensive.
And that was an example of the cheapest watch. When speaking about 30K - 50K - 100 K and even a lot more, NOBODY would feel sad because his watch would go up with 500 or 1000 euro.