It strikes me that a major moving in to claim land for itself, upon finding a good strike, could use this leverage to buy juniors and not feel so much of a pinch having to buy 100% out of pocket.  Their land would provide financial gravy so to speak.  It could also provide them with the extra leverage to win in a bidding war if it came to that.  Knowing they have the resources, they could bid higher and still come out ahead.