In my experience, having used loads of different brands and worked in retail selling outdoors stuff, there is bugger all difference between a lot of Decathlon gear and more spensive brands. As flatfish says, some of it is tat, but quite a lot is of decent quality and equal to most brands. North Face isn’t a particularly brilliant brand anyway. Mid-range at best, overpriced mostly, imo.
Considering most stuff is made in big factories in China etc, there is often no difference in quality. The difference in price reflects the brand identity more than anything else.
And as for ‘bike’ brands; some stuff is a complete rip off. Just big prices slapped on bog standard kit, with a load of marketing hype convincing people to shell out loads.