The white hope campaign might not have produced great heavyweights, but it does seem to have produced a lot of big heavyweights. Jess Willard, Luther McCarthy, Fred Fulton, and Carl Morris were all products of the white hope campaign.
Yes I think it was decided that in a fight to the finish a bigger man might be able to outlast a better fighter. Either that or it was decided that a man like the previous dominant champion needed to be searched for. A new Jim Jeffries. But whatever they were every last one was a real boxer. Never think they were just big farm boys. They all fought lots of time in a tougher era than now. All of them would be relevant today.