With selling it, that is.

Remember what happened to the later Apollo missions? They became "routine" in the eyes of the public, which lost interest -- including the few who voted, who raised no objection to Congress curtailing Apollo after 17.

How many STS missions do you think an average person can recall, if asked? My bet would be two: Challenger's explosion and Columbia's burn-up. The rest are "routine".

Do local news sources (TV, papers) publicize dates and times of ISS flyovers? Nope. Not anywhere I've lived in the last few years, anyway.

As I wrote here, prompted by a link I found here in the Space board, the people whose support is needed most are the 51% who seem to believe that space exploration is an expendable extravagance -- even though it amount to a mere seven thousandths of the Federal budget.

(I presume, by the way, that the budget in question is the one that can be spoken of in public, the non-"black" one... and that it doesn't count emergency appropriations for other forms of adventurism. That latter inclusion might bring NASA's relative share down another thousandth or three.)

The answer to the Fermi Paradox is actually quite simple: Lack of interest by the people who eventually have to pay for the infrastructure to become a spacefaring civilization.