Absolutely Apple uses other manufactures for parts, in which they're in direct competition with. Samsung was the only supplier they could meet Apples demands for 92 million OLED panels for the iPhone X. Apple also continued a contract with LG for future OLED Panels after the Samsung contract expires. Competition is good, but these suppliers do need each other for the success of their products as well.
Apple better hope LG can improve the quality of the mobile OLED screens by 2019. Funny how LG can make great OLED TV screens but such mediocre mobile screens.