It really does happen. The question is how you keep on renewing a country and a people when things are going "just fine".
There is really something to the idea that strife / disaster / starting with nothing causes you to yearn to be better and invest in things that you wouldn't do when you've already made it. You raise kids in wealth and they rarely have the same drive as their up-from-bootstraps parents. And maybe nature's checks-and-balances on this is that eventually those people who struggled through adversity and built things get comfortable. They stop wanting to invest, and instead want to extract. It gets hard to get people to be willing to sacrifice like they did when they were young.
The USA has already made it. In its own mind. So most people are not desperate to have high taxes, high effort, low potential of immediate reward -- the kind of thing that builds things that last beyond your children.
Now it's either 15% returns or it's not worth it. Or vote out anyone who proposes something that costs a lot. And only when we see other countries whose people had to struggle from nothing do we realize that standing still sometimes equals going backwards in the global race. It's how you end up landing at La Guardia, trying to take a subway, and wondering how your capital of prosperity could have gotten so bad without anyone noticing.
I don't know how exactly to incentivize a contented culture to be willing to sacrifice. I am sure, though, that social media and polarization and targeted outrage of special interests against any potential idea doesn't help. It's a real puzzle how we're going to get out of this funk and not be passed on the highway by lots of others.