Sure you can get better precision with your phone or even any cheap watch with a quartz movement.
But it just seems amazing that something so small made just out of springs and levers, so small moving mechanical parts with no electronics, can keep time with a -2/+2 seconds accuracy in any wrist position (gravity) and any temperature (stuff shrinks and expands).
Diminishing returns / asymptotic change.
I think the last major advancement was the coaxial escapement in the 1970s:
* https://en.wikipedia.org/wiki/Coaxial_escapement
and as per a sibling comment, the spring drive:
The incredible engines we have now, the robotics, self opening car doors, surgical robots, those heart valves that they can implant through an artery in your groin and expand in your heart, surgical navigation and spine/brain surgery, space travel....
They don't need to be expensive though. A Seiko 5 or a swatch mechanical automatic are 100 bucks and capture all this wonder also.