just a few thoughts:
- No maker today does every part of his movements.
Rolex is (besides ETA) the only maker to make hair springs, but apart from this parts as screws and springs are ordered from outside. Shock protection (such as incabloc) can´t be made by the makers due to patent infringements.
In a "traditional" sense of making every single part of the movement, i would say there is nearly no manufacture for far more than 100 years.
Since the upcoming of industrial production after 1750´s, almost any maker had at least various parts made by others.
There are many reasons to do so and the most important ones are quality and price.
If you make precision parts, you will have bad pieces or defects in your production. That´s something impossible to avoid (not only in watchmaking) and it´s much easier to control if the series is bigger. If you need only 1000 pieces of a certain part with a few 1/1000mm accuracy, it will be very hard to do them equally. It´s much easier to go for a larger scale production run and pick up the best 1000 pieces.
In addition, production of precision parts require extremely expensive tooling and machinery such as spark erosion cutting machines. One of this can easily cost a few 100.000 US-$ which is quite an investment if you do only small series of some hundred or 1000 pices. Besides, these machines are really slow. Often not more than 10 parts per hour can be done. And you need qualified personal.
That said, making every part in-house may not result in a higher quality, but certainly in much higher prices.
- The use of outsourced ebauches like ETA is even more a question of prices.
The GP 3080 column wheel chronograph movement in the "Vintage45" is much more expensive than a calibre 2280 ETA-base movement in a "Pour Ferrari" chronograph, a GP 3200 movement in a "Classiqe Elegance" is much more expensive than a calibre 2200 ETA-base movement in a "Pour Ferrari".
Of course GP can do their own movements, has done so for more than 200 years and will emphasize on those in the future.
They do so because there is a market for these watches. And there are collectors and enthusiasts who appreciate the quality inherited, willing to pay a much higher price. If you look at the "Pour Ferrari" (ETA base) and the current "2000" (GP base) watch lines, the difference in price is obvious.
The development of a movement is reportedly not much easier than a car´s engine. The costs are huge and at least in the 7 digits. And it takes much time: For example, Patek is working on in-house chronograph movements for many many years and still it´s a project. IWC´s in-house automatic movement has been designed in 1947; but the very first examples ready to sell were made in 1950.
This investment has to be divided by the number of movements one does. Making a simple automatic movement easily extends 1.000.000 US-$ investment for the brand. Given the annual production of about 16.000 watches (including all lines), a watch with such a movement is much more expensive than a watch with an ETA base.
This is one of the reasons Lange does hardly any steel watches; a Lange 1 in a steel case would not be much cheaper in store.
And of course, GP´s tourbillons and minute repeaters are in-house and hand made. The necessary parts (more than 100 individual parts for a tourbillon escapement) aren´t readily available. The assembly of those requires experience and much time, not including the hand made finishing, decoration and regulation. That´s the reason why these pieces are so special and "mass production" of more than a few hundred pieces a year is not possible.
Conclusion: Of course GP does provide in-house movements (and many of them) if you are willing to pay for this premium.
And my very personal take: I don´t think every in-house movement is better than a base movement only because it was made in a manufactory. There are many very good watches having a ETA, Lemania, JLC or F. Piguet base movement. It´s not the movement, but what you make of it. On the level of production costs, an ETA 2892-A2 can be $50 or $100. But it easily can be more than $1000 if refinished and detailed by hand.
Greetings from germany,