I think a lot of the "me, too" producers tried to cash in on the GoPro excitement. Flooding the market produced fratricide, each maker took to much market share and... bye-bye. Of course they didn't any support infrastructure to speak of.
GoPro, according to an assessment that I'm inclined to accept, wasn't really all that advanced. They put together some gee whiz features, some of which have some use (e.g., GPS for tracking position in a video production) and that IMHO are almost silly (voice commands). But the imagery that I get from the Hero 5 Black is bad enough to move it to time lapse-only. IMHO at least the H5B is more sizzle (GPS, voice) than steak (imagery). Look at the grass, the trees in the distance, and pixilation in the road. Even the reflection of the map lacks read detail. No thanks.
The idea of any phone seriously competing with a "real" camera strikes me as wishful thinking. NTL, multiple lenses, even real zooming is showing up. And that applies to video, too. But shooting from a bike (powered or not), skies, surfboard, etc. isn't likely to happen. Ditto for dash cams. Action cams probably won't vanish but will be a specialty item covered by a few companies.
Someone raised the idea of of license plate recognition in a dash cam. I guess using a smartphone would make that practical. Or not.
I'm hoping the SJ8 can top the SJ7 imagery, although that's probably harder then beating the H5B.