The reason right wing literature survives is because it's based on natures laws. Leftist can't declare war on natures laws and win. They may win a few small battles, but they always lose the war in the end.
Leftists base their worldview on humanism, the belief that starting from the reason of man, all the answers of the particulars and absolutes can be obtained. They might find a few particulars, but you can never obtain the absolute.
You referenced “natural law”, which really is a reference to how God created creation, and the rules and laws inherent in that creation. That’s an absolute outside of the reason of man, so the left rejects it in favor of their own “intellect”.
There’s another most important aspect of socialism and marxim (the two go hand-in-hand and mean the same thing as ‘progressive’ means today as spouted by that famous fat-head, Hillary Rodham Clinton: “I’m proud to be a progressive.”) those who claim that ‘philosophy’ are imbeciles.
Their writings, their speeches, every damned thing about them rings as moronic, beyond sophomoric and displays them as candidates for strait-jackets in a booby hatch.
Instead, they are honored, practically worshipped by a dangerously large portion of this faltering nation. Faltering? Practically destroyed by large segments of both of our political parties.
If America doesn’t wake up we’ll be embracing someone under the order of Benito Mussolini, or more luckily a benevolent despot like Francisco Franco, who I personally admire for what he did the the communists who were destroying his nation.