It started right away with "big budget" devices. Devices that were hard to program and had to sell huge numbers to recover their investments. Those devices were then aimed at the "fitness tracker" market and nothing else. Not even displaying the time was a priority any more. Also screens have been to small compared to their sci-fi counterparts and nobody bothered about the input problem. In fact in order to use (=program) all of those computers you had to use a separate computer with a special development environment. Any idea you have for such a device will be eliminated by the frustrating experience of installing that environment and actually doing the programming. Also, since most of those devices run fully fledged bloated operating systems, they needed to recharge quite more often to be useful.
What we would need is a simple system centred around the software a digital watch would usually run, then add hooks to allow people to hook their own code to experiment with the system. This sort of "experimental phase with geeks" is rather important, but the modern smartwatch industry tried to skip it.