Is it really such a bad problem to have? A lot of races have lost elite fields (Cleveland, Houston, LA, Detroit, Austin, etc.) from the days when marathons were not popular either as a participation sport or an elite event. Now that the sport is popular, there is also a lot of money going into professional development. Many of the major races have Olympic development programs that comp entries, provide housing/travel support and bonuses for getting a qualifier. Back in the day, you would be lucky if the race director would let you pitch a tent in his back yard.