I believe Rolex started as an importer/distributor and set up in London, and only moved to Switerland because of high taxes imposed during the war.
I imagine that they struggled like any microbrand would today: no watchmaking expertise, not even swiss !
To me Rolex made their own success against the odds with licensing and marketing.
The first waterproof case (oyster) and automatic movement (perpetual), if I'm not wrong both were licensed technologies, not in house. Credit to Rolex to breaking the mould and trying to change the concept of the watch from a fragile instrument to a tool watch.
But to me this would not have been enough without marketing. Probably the first sports endorsement with the Rolex Oyster across the channel. Mind you it was a woman too so it was big news then.
For the longest time Rolex was also the biggest watch advertiser in the world, investing in TV, print, point of sale materials and of course endorsement e.g Wimbledon.
To me Rolex is a great story because of the innovation at all costs,
in-house production is only a means to control QC, but not an end in itself.
Don't get me wrong i think brands like PP, ALS do great watches too, and they deserve what they can get with their highly finished products. But me the common chor-lor folk - the finest standards of jewelry would look out of place even on me