GoPro declined 31% last quarter. To save itself, GoPro has decided to slim down its lineup.     Link

Now if they'd only do GPS data logging like a Garmin Virb with on-screen data overlays, a GoPro Hero 5 would be more interesting.
 
The Session and the entry level cameras were a big mistake. The Session makes no sense and the entry level cameras have to price match China knockoffs that are 75% cheaper with comparable features. GoPro made some wrong moves in 2015. It's not that they lost share in 2015 by getting into the cheap market. It's that they can't compete with premium pricing in the cheap market. They priced themselves out of viability.
 
Ultimately, the problem with the GoPro line is they're selling a $100 camera for $500 then wondering why no one buys it.

Never was impressed by the ones I tried that others had bought. 
 
Then the much cheaper knockoffs flooded the market.
 
As GoPro does not seem to have any patents to protect its market share; it needs to innovate before it perishes.

MSim
GoPro has the same problem Camcorder market does. People are happy with the quality they get by using a smart phone to record with.

 I agree with this.

After the birth of my child my mother in-law picked up her iPhone5 to take pictures. It was literally next to my DSLR Nikon... 
 
phones have nice cameras, but they're just that, nice phone cameras.