the whole thing of upping the requirements is kind of ridiculous. if you have so many people doing more than 600k miles every two years, you should have ways to treat all of them well.
actually the total amount of people you have in top status does not matter. you should set the requirements so that to achieve top status you have to give the airline great enough revenue. and if the current requirements for HON are not enough for an airline to consider me a top customer, then quite frankly that airline is getting slightly too arrogant in my opinion.
if you want to limit the number of people, why not simply create the top500 customer circle?
everything else is illogic.