Years ago when I had Rolex they were a fraction that cost for complete overhaul.
Yes, you are right. Most watch manufacturers charge an Arm for nearly nothing.
Rolex is expensive when you buy it, but their Revision incl. repair is a bargain compared to others. I had a Datejust running 23 Years nonstop, then it stopped working (Dry). Rolex made the repair with new parts and polish for 500$ only. I expected much more, because it was not working anymore.