Originally Posted by Pylon
Though I certainly can't improve upon the great explanation written by djf881, this video
by the fine craftsmen at A. Lange & SÃ¶hne should highlight a few areas where their watches differ, from say - a $3k Omega.
Yeah. The hand finishing on a movement is very painstaking and very expensive:
Here's a Lange:
Here is a Patek:
By contrast, this is what is beneath the caseback of a Rolex Submariner:
You can see the Rolex lacks the hand engraving, which takes a lot of labor from highly skilled watchmakers and is therefore adds a lot to the price of a watch. This extra work is entirely ornamental, and can't even be seen if the watch is on your wrist, because it is displayed through the back of the case. This kind of work is highly coveted, because it takes a lot of time and there aren't a lot of people who can do it.
The Rolex movement is designed for function rather than for display. The Submariner is rated waterproof to 300 meters, deeper than any rec dive and most professional saturation dives. This is a thing made to do a job. By contrast, the Patek is probably waterproof to 25 meters, but realistically, you'd probably want to take it off when you wash your hands. The Rolex is a very precise mechanical watch, and it maintains that supervision by a high-tech manufacturing process, but it's not about being painstakingly handmade.
The Patek movement is also designed to be very thin. An automatic watch contains a rotor which spins when you move your arm, to capture the kinetic energy of your movement to wind the mainspring. On the Rolex, the rotor is the large, fan-shaped steel piece that covers half of the movement. On the Patek, it's the small gold half-moon shape with the Patek logo near the top of the watch. Apparently, they can wind the watch using a smaller roter by making the rotor from 22 karat gold, which is very dense. Kind of cool.
Also keep in mind, the Rolex is designed to be durable and accurate, from the top of Everest to the bottom of the Atlantic. The Patek is designed to be incredibly thin, and the Lange is designed in large part to look really pretty in a display case, although it's also an extremely complicated perpetual calendar watch. The Rolex sub in steel costs around $5000. A self-winding Patek Calatrava is about $18-20k. That Lange perpetual costs around $140,000.