Technology built to last
I spent some time this morning relaxing and watching this video by my friend Marshall. In it, he services a Rolex watch that its owner had worn daily for 53 years before it stopped running. And as I watch it, I look over at my Galaxy 4 watch charging next to me. I greatly enjoy and use it, but I also realize I'll be lucky to get a tenth of that life time out of it.
Obviously, a big problem is the continual climb of technology.
Analog watches hit a relative plateau decades ago, where the innovations (largely speaking) stopped and so the differentiating factors became build quality and life. We are still far from that as far as digital technology goes with data, wireless, screens, processors, all continuing to improve and change.
There is little reason to build a computer, or a smart watch, to last 50 years outside of industrial and governmental uses. Especially for an accessory like a watch, it will always rely on another service to provide updates, screens, applications, etc. It would require an incredible feat of engineering to future proof a smart watch such that it would be able to easily be ported to any future platform. Not impossible, but certainly difficult.
That said, if someone came along and sold a smartwatch able to last fifty years with a robust futureproofing documentation, and it satisfied my needs for its functionality as well as aesthetics, I'd heavily consider purchasing it almost regardless of price.