Earlier quoted context omitted.
People want immediate results. Investing in something that won't necessarily bring results for years or decades (or centuries in the case of space exploration) is rarely going to be popular. At least here in Australia, a common comment on something like this is that we shouldn't spend money on this sort of thing when there are people starving and dying in the third world. Then the typical comments on, say an article…
I wish Australia would spend some more money on space based projects, imagine if the US decided not to make any major investment into space, the planet as a whole would be getting nowhere on space based research projects.
The space shuttle, for instance, persisted not for the scientific or technical advances, but that it sent money to lots of political constituencies, which alone made it viable. The Hubble, while giving us spectacular images, was still horribly overpriced and NASA ended up paying for it twice over (once to send it up and twice to send the shuttle after it).
There wasn't a lot of opposition to the shuttle and the ISS from within NASA (for 'eating up the budget') because they were aware that budget only existed because of these high-value items. They might have liked to have the money for other things, perhaps, but political money doesn't work that way.