It was inevitable and kind of expected.

The US wasn't built on that solid of a foundation. In fact the founding fathers have said explicitly that said foundation - the Constitution itself - should be a living document updated regularly by the people, for the people, to reflect the changes in the world and in the people themselves. It was literally written at one of the most prominent times of change, so of course those who saw said change and were responsible for enacting it, weren't idiots who thought things would never change!

The first cracks appeared in the US a hundred years later with the industrial revolution kicking into high gear and transforming the so far mostly rural, self-sufficient communities into manufacturing giants. That's when factory and mining towns began to boom, and when the US truly began to claim its world power status - without adjusting the laws of course since it benefited the handful few who managed to get their fingers deep into those oh so lucrative pies.

And it's not like there haven't been warning signs of the impending capitalist doomsday. Capitalism was literally built on the back of the industrial revolution (which allowed the means of production to transfer into and concentrate in private hands), and immediately people saw the issue with it - no wonder Marx saw the need to work out a competing socioeconomic system that, if you think about it, was truly in the spirit of the American independence and the US Constitution (aka by the people, for the people).

All that capitalist rush? That allowed a handful of people to become obscenely rich, without the curtails of previous obscenely rich (aka kings, royalty, nobles), allowing them to grab power without any of the responsibility. Kings paid with their heads for their wrong decisions, but in the US, that was deemed excessive, so instead y'all elected people who then got paid off by said obscenely rich to go against the people electing them... and the worst that happens was that the elected official got rich, then got replaced by another who got bought out the same way.

And all that money/power concentrated in such a small number of hands would ALWAYS lead to them wanting more and more until they sucked the host dry like a parasite. There's no symbiosis with capitalists because wealth (resources and man-hours) are finite, unlike their greed. And since the US made it harder and harder to amend the constitution, to make that document truly living and serve the people... The fall thus became inevitable.