4k on a gopro 13 is far far far clearer. And the stabilization is night and day. Half my hero4 videos are mostly blurry shakes and quite jarring to watch, with a bad fov. The stabilization on modern gopros is magical. The bitrate and quality is orders of magnitude better. You can now pull good quality stills from the video if you want. Hero4 can't handle anything but perfect blue sky in the middle of the day. Etc etc

Yep, something must have gone horribly wrong with QA.

Frankly, after 4k/30 and 1080p/60, there are strong diminishing returns, because most people these days watch videos on their phones in suboptimal conditions (or older desktops that may still be on 1080p), so what are they going to do with your 5k/6k video?

Sure, you can keep doing minor improvements to sensors and optics, but for a consumer it will not justify getting a new model for $500.

Also, competing with smartphone cameras which have gotten better over the years. I bet 99% of people would not be able to tell a gopro video from a phone video.