How Are Mechanical watches "Timed"?

If you look at old mechanical watches, high quality (very accurate) watches are said to be “adjusted”-this means that the balance wheel has small weights screwed in to the periphery of the wheel-these would be carefully screwed in (or out) to affect the speed of the wheel, and hence, improve the accuracy of the watch. Having four adjustments (where the watch would be timed in four positions) was done to produce a watch with the ultimate accuracy.
Now, if you look at a modern mechanical watch, the balance wheel has no adjusting screws-it is a plain wheel. So how are modern “chronometer” (highly accurate) watches adjusted? And , given that the balance wheel will always have some imperfections, , a quartz watch will always be more accurate-why aren’t quartz watches automatically given “superlative chronometer” status?

I believe it’s simply a matter of finer control in machining the parts that makes adjustable weights unnecessary these days. The wheels and escapement are probably laser-cut by cool robots rather than carved by hand.

As for quartz watches, even the cheapest digital quartz Swatch will be more accurate than a fancy mechanical Rolex. “Chronometer” is a term usually reserved for mechanical watches, though. Even though an electric one is clearly superior from a technical standpoint, high quality mechanical watches have an enduring aesthetic and coolness factor that still commands very high prices.

Mechanically there are a few ways it can be done. Imagine that the driving shaft has is shaped like a cone and engages the wheels that actually turn the hands; if you raise or lower the drive shaft with respect to the watch mechanism, you’ll change the speed at which it turns. There are also pendulum wheels that can be adjusted to swing at the correct rates.