I had a msi gtx 770 and a msi r9 290x, and somehow the 290x were so much easier to install onto the motherboard while the 770 took me a lot of effort to push it in. Even after the 770 was installed, the little flip on the motherboard still did not seem like it was flipped all the way up as a successful install should look like. The power connector were also much easier to plug in for the 290x. This made me wonder, does MSI produce the whole cards by itself? Why is there such a big difference in the physical details between the cards.
Usually the Nvidia and AMD only provide the GPU, the rest(cooler, pcb, ram, vrms, etc) is done buy the cards manufacture. Nvidia does make and sell some reference cards. AMD will also make some cards but usually just for samples.
Like big said. AMD and Nvidia supply the chips to third parties that develop the PCB and components of the whole video card, they will also tune the clock speeds of the GPU cores and vram to their own market specs with their own market cooling solutions.