"there just isn't money, either private or government, for a mission for a rocket that size..."

People used to say the same thing with the first supercomputers.

Now our entire planet (governments and corporations and even small companies) are falling all over themselves to get more and more computing power in the form of rack-servers and advanced networks to handle high bandwidth traffic.

Today's super-computers, or server clusters are often made up of components of cheaper computers (just as Elon Musk is trying to build Falcon Heavy by putting together components of cheaper rocket technology and engines).

I strongly suspect NASA's chief Charlie Bolden is repeating history when he says such things, just as Thomas Watson, president of IBM, once said in the early days of computers:

"I think there is a world market for maybe five computers."

If you have vision and imagination, I feel it is obvious that there will there be much more of a market for heavy lift rockets, beyond the equivalent of 5 old computers.