Probably that it's a fight one can't "win". Better focus on the brand and making people aware of it and it's benefits.
My point is that they never bought the right for the design from OEM from whom they bought their first digital cameras, and that OEM itself never bothered to limit access to the design as it makes no money to them.
And my point is that has nothing to do with why there are cheap knockoffs as there are cheap knockoffs of all well known consumer electronics (fake iPhones even come out before the real iPhones!).
I don't think the rights to a 10-year-old design have much to do with what GoPro and their copycats are selling now. Knockoffs are everywhere, especially where the market-defining product has a large margin.
> "might've been wondering why GoPro never seemed to assert their rights."
That it has nothing to do with asserting rights, how the original product was developed or anything GoPro has done since. It's just how the world works.
It's how the world works after 50 years of American CEOs shipped all of their employer's IP to China in return for the margin boost that would give them a better stock option bonus for the 5-7 years before they could wash their hands of the company.