You're leaving out part of his argument which justifies space exploration as inherently valuable beyond its technical and scientific contributions: a paradigm shift of the human condition, brought on by our increased awareness of our place in the universe.

"Although our space program seems to lead us away from our Earth and out toward the moon, the sun, the planets, and the stars, I believe that none of these celestial objects will find as much attention and study by space scientists as our Earth. It will become a better Earth, not only because of all the new technological and scientific knowledge which we will apply to the betterment of life, but also because we are developing a far deeper appreciation of our Earth, of life, and of man."

Imagine if we found evidence of past life on Mars or Europa. It would change our understanding of life on Earth. You can't make that discovery in a lab.