From Henry Spencer, over at sci.space.policy:

…as Jordin Kare noted a while back, the elevator people say they could give us launch cost of a few hundred a kilogram for a ten-billion investment… but there are plenty of rocket people who think they could match or beat that launch-cost number with a lot less up-front money. “They aren’t Boeing, but neither are you.”

And the nanotube materials that the elevator people need will do wonders for rocket structure, well before they’re good enough for elevators.