A watch repairman told me that most watches regardless of price are made in the same handful of factories (mostly in Asia). Not sure if it's true or not.
Well, that depends on the watch.
It's just like with sunglasses, most sunglasses are now made by Luxottica.
And most quartz watches have Seiko movements. However, Orient makes their own mechanical watches. And the upper tier watches, like Audemars Piguet, make their own movements.
Just like Moscot and Serengeti still make their own lenses, whereas Ray-Ban was bought up by Luxottica and is now made in Italy, not the U.S.
It's not a big deal, Seiko supplies excellent movements, and pretty much every brand will note under the specs what movement the watch uses.
Here's a link to an article about watches with 'in-house movements'.
From that article:
Many luxury brands manufacture their movements themselves, including
Rolex, Vacheron Constantin, Audemars Piguet, and Patek Philippe.
Other luxury brands use prestigious manufacturers, including:
ETA
This is the most famous
Swiss manufacturer. Swatch owns ETA, but it has also provided movements for other high-end brands throughout history — Omega, Breitling, Longines, Hamilton, Tissot, Rado, Panerai, Sinn, TAG Heuer, Oris, and even Uniform Wares!
Miyota
Miyota is a Japanese manufacturer that was founded by Citizen in 1959. It’s used by Halios, Zeppelin, Helson, and Obris Morgan.
Seiko
Seiko is known for manufacturing some of the best movements out there. Many luxury brands use Seiko movements, including Breitling, Armida, and Invicta.