I agree with some of what you said but mainly disagree with your analysis of poor libertarians. I will use the USA as a model for my post.
Historically we should expect to find more economic fluidity amongst white people, meaning they’d be able to move from worker to labour aristocracy/petty bourgeoisie. The classic example would be for a white worker to labour for a time at a decent paying job, save money, buy a house, and start a business.
So as we see, the class lines would be more blurred in the past because of the stronger wages and free time of labourers, and so there becomes no real need in the present to tie poorer libertarians historically to immaterial things since their interests in the past were absolutely material and aligned.
With the polarization of the economy the class lines become more defined. So then the poor libertarians, stuck without any mobility as workers, become very reactionary and oppose any groups that threaten their elevated or once elevated position. Those who are petit bourgeoisie themselves, even though they may not be poor, are threatened with becoming workers again.
This plays out nowadays as the libertarian to fascist pipeline, though American libertarianism is already inherently reactionary by being supported by colonialism and imperialism (as opposed to, for instance, a petit bourgeoisie in another country trying to rid itself of the shackles of colonialism).
In the American case libertarianism is a petit bourgeois (and white i.e. settler, very key here) ideology that fits very well with the standard Marxist model of the petit bourgeois being the source of fascism.
As much of a steaming heap of crap that movie was, there are worse movies.