As revealed by iFixit, Samsung collaboration never worked well, with parts that were too expensive, and/or glued together (like a battery+screen replacement!)
Moreover Samsung never really tried to make their designs more repairable.
ifixit blog post is full of episodes, like when Samsung and iFixit announced an upcycle program, and then Samsung disappeared.
Ok, Samsung is cleared not interested in making their product repairable.
Samsung has been leading the charge towards enshittification for many years.
A dominant market position will do that to you, it seems.
I think there is more to it, but it definitly helps. Basically, there are still people that make those decisions.