You're right regarding 4K, but I think people will rather use 60fps for the kind of usage the gopro is meant for. So it's really 4K vs. 1080p, and I doubt "99%" of the population will go for 1080p.
1. The Black does not shoot 4k at 60fps.
2. 99% of the population does not have the means of displaying anything over 1080p, let alone the power to edit it into something watchable. And neither will any significant percentage of people get a 4k screen in the foreseeable future.
3. This last point is even stronger in reference to the DDF "population", where many (if not most) don't have a TV at all and would light view their footage on a computer monitor.
4. The typical GoPro costumer does not use the camera for what it is intended for in the first place - extreme sports and the like. Most people dont need crazy resolutions or frame rates of the road they're driving on or their kid on a bike.
5. 4k downsampled to 1080p viewed on a computer monitor is in no way* any better than 1080p / 60fps. In fact, it's worse when you consider its additional horsepower and storage needs.
So I stand by what I said - for 99% of the population, seeing and controlling what you're actually shooting is far more valuable than a couple of frame rates that you'd never use.
*There is one way that it is better, which is extracting stills from the video - 4k is simply far better than anything else. But then theoretically you could do that from a 15fps video as well.
