Imagine a United flyer who spends $100,000 in a year flying LH back and forth across the ocean. Why would United have any interest in handing out their top tier status to that traveler, even if they were valuable from a revenue standpoint?

GS benefits (the ones that are beyond 1K) are really only useful when flying on United metal, so it makes sense that they would only give out that status to those who actually fly a lot on it.