Samsung is the only company in the world that is capable of making enough OLED displays, NAND flash, and DRAM in the quantities that Apple need for the mass sales of its iPhone.
https://www.tweaktown.com/news/59354/samsung-make-more-money-iphone-galaxy-s8/index.html
https://www.tweaktown.com/news/59354/samsung-make-more-money-iphone-galaxy-s8/index.html