Even the watches that have recently sold for crazy prices would not have been good investments. The Patek world timers, that have recently sold in excess of $1m, probably sold for at least $500 when they were new in the 1930s
so that is an increase of 2000x in 70 years, or 11 doublings. That means that the value was doubling every 6 years, or about an interest rate of 12%.
Just an interesting bit of math
-a