No one would fund pure research except the government.
I'd rephrase this to say, no science serving 'the public good' but not profitable to the funder would get funded without the government sponsoring what's good for society.
So we'd have *tons* of funding for the profitable things, but practically none for other things.
This is partly why the Moon project - which got 5% of the federal budget at the height - was such an effective combination of furthering science with the political backing.
Even if it took the Cold War to get people to really want to 'beat the USSR'.
Things that advance the human race that aren't short term profitable generally happen from the government doing them on behalf of the people with their money.
Of course, many Americans haven't seen so much of that. Go back to Kennedy, and you find a lot of the agenda talking about these sorts of priorities for government.
The great achievement of the moon landing wasn't just the science - it was the political too of people supporting such a common societal goal at great expense.
When that public spirit existed with the government doing such things, note the cultural result as people thought there would be great progress fast - all kinds of movies and shows assuming within a few years that there would be great advancement, with man more places, with great science, and a lack of poverty. Note how today, generally the 'post-disaster' scenerario with the few stragglers is much more popular, and there's not nearly the progress.