Foxconn isn't just an assembler. Foxconn is a contract manufacturer. They have mutiple subsidiaries involved in display tech.
As I said, I don't doubt Samsung will be a big player in mLED. They just won't be what they are in OLED. For a lot of OLED's history, Samsung essentially had no competition and it allowed them to dominate. That isn't true for mLED. Lots of players are vying for a seat at the mLED table... Apple being one of them.