I do understand where you’re coming from, but there are certain fundamental misunderstandings that undermine your argument.
The first being the assumption that there has ever been a Left in America. From a British viewpoint, you have the hard-Right Democrats and the ‘slightly-to-the-Right-of-Genghis-Khan’ Republicans. Not even Bernie Sands would dare suggest anything as radical as our NHS -a universal, tax-funded, free-at-the-point-of -use healthcare system where the hospitals are publicly-owned and the doctors and nurses are Government employees.
Secondly, there is a failure to grasp the complexity of the Left/Right divide. A complexity brought about by the difference between economic and social ideas.
In Britain, for instance, working-class people are solidly behind the NHS. They would prefer the utilities, public transport and strategic industries such as vehicle manufacture ( cars, aircraft and ships) to be nationalised. They want to see the rich paying more tax, and a closing of the gap between rich and poor. They want strong trade unions who can face-off against the bosses on equal terms. They like the idea of generous, no-strings grants so that their bright kids can go to University, but they also want proper, free, vocational training and apprenticeships for non-academic youngsters. So far, so Left.
BUT. These same people believe the criminal justice system is too weighted in favour of the offender/suspect. They believe that corporal punishment (the birch) and capital punishment are both effective deterrents and proper punishment because they believe that some people are just bad by nature and need to be scared into good behaviour or disposed of. They are anti-immigration because cheap foreign labour pushes wages down. They don’t like foreigners because you can’t trust the French and Germans — leopards don’t change their spots — the Japanese wrecked the British car industry and the Yanks are, and always have been, bloody useless! A little bit Right, there.
Then you get the race thing. In Britain that breaks down to not caring what colour people are, but being generally pissed off about people coming here from Pakistan or Bangladesh or wherever and not changing the way they behave. They don’t dress properly, they don’t change their names, they treat their women like crap, they don’t go to a proper church on a Sunday, they have a go at their kids for making friends with white kids, and so on. Worst of all, they don’t bother to learn English! (Overheard outside my grandkids’ school: “That woman’s lived in this country for 20 years, and she still doesn’t speak a bloody word of English! If I was to move to Pakistan, the first thing I’d do is learn Urdu! That’s just manners!” The speaker, by the way, was Afro-Caribbean.)
Other things are also complicated. Womens’ equality? “They’ve been in charge for this long, so maybe it’s time they gave us poor blokes a chance!” Gay people? “I can’t say I understand it, but it’s their business. Leave ’em alone!” Transgender? “ Not their fault. More like an illness, isn’t it? If they want themselves put right, fair play to ‘em.” Non-binary? “If they can’t make their minds up if they’re a boy or a girl, they're dafter than I thought!” Bisexual? “Greedy gits!”
Marx, you see, thought only in terms of economics, not the complexity of the human psyche. He never predicted a middle-class full of people who owe their status and lifestyle to capitalism, but have heads full of liberal social ideas they picked up at University. Nobody ever dreamed this lot would take over the Labour Party and turn it into the economically-Conservative, socially-liberal abomination that was Blairism.
A final fundamental misapprehension that everyone suffers under is that Fascism is the extreme of the Right. No, as Soviet Russia then and Communist China now prove, Fascism is the extreme of the Left. The extreme of the Right is Anarchy.