Samsung has already done this to a couple of competitors before. HTC had to switch to TF-LCD display back in early 2000's when Samsung wasn't able to supply enough OLED. Samsung's dominant share of mobile OLED (as the largest producer and consumer) hasn't really changed much for the past decade, at around 95%. But this all comes down to supply and demand. I doubt Samsung would maliciously shutdown their OLED production just to piss off their #1 customer. After all, who can say no when even their worst enemy comes begging with a wad of cash?