Pebble smart-watches. I had them from the original kickstarter, and eventually had a Pebble Time Round which I loved. Whilst I now would never buy a smartwatch, I think that theirs were by far the best. Slimline, with a great UI, and nice functionality, and also not locked into either mobile ecosystem. I'm not entirely sure what caused their death, but my personal view is that they tried to become too big, and I don'…
I think you're spot on here. They had a perfectly viable 20-30 person company going in a nice stable little niche, and then the smartwatch hype cycle reached its peak and VCs threw a ton of cash at them along with a mandate to become the Next Big Thing. And so they hired way too many new people, churned out too many new models, and collapsed when the market just wasn't there.