I think that people who are not well traveled are not even aware of this slide, but we have been moving towards becoming a highly stratified developing nation for 20 years now. The armored car is just one striking example, but there are dozens more I can think of off the top of my head.
The U.S. has always fundamentally been like the Central and South American countries, just with a thin layer of Lockean rule of law and property rights.
That layer is quickly eroding. The U.S. will become more like Mexico or Argentina (for instance) over time.
Love him or hate him, Trump did a lot to advance this timeline. You can see that his style is much more reminiscent of Central and South American politics. His followers want to replace the Lockean style with a political system built around a strong central personality.
But it seems to me the opposite is instead true. Are you perhaps suggesting the non-immigrant, white males supporting the current political climate look up to the immigrants as role models?
Immigration is not the reason the U.S. is not losing the Lockean "rule of law and property rights" layer.
It's losing it because other ideas have come to predominate the intellectual landscape.
While still a situation that's a direct result of and reflection on US policies, it may be a more specific issue than a general national trend towards greater stratification.
[1] https://www.coloradopolitics.com/opinion/at-risk-of-robbery-...
[2] https://www.firstcoastnews.com/article/news/nation/fugitive-...