If UA manages the GS membership properly it should represent their most profitable customers, not their most loyal customers. That is why the criteria are somewhat fuzzy to us as flyers, we have no true measure of our profitability to the airline. Loyalty may be viewed as a reasonable proxy at times but is certainly no guarantee of profitability. I have a friend that flies three times per year. She buys cheap tickets on leisure routes six months in advance. She is fiercely loyal to United. I doubt she is particularly valued for her contribution to the bottom line.