I'd have to read his book again (for the first time), but as I recall, Fukuyama wasn't all celebration. There was some uncertainty about whether the culture of "the last man" could perpetuate itself. Also a feeling that Europe was further along that road than the US.
"Ideologies of the 30's" were diverse, ranging from the wisdom of Franco, -- who, I would argue, was the only wholly successful national leader of the 20th century ...
That whole Spanish tragedy looks like a great bloody detour to get where the country would have gotten anyway if its leaders had had enough sense not to destroy the country.
I don't know what the answers are, but sometimes the solutions that get proposed don't seem likely to solve anything. Young Venner fighting to keep Algeria French when De Gaulle had already had enough of the war -- was that really a wise course? What brings me back to Fukuyama -- and behind him Strauss -- is Venner's celebration of what they called "spiritedness." You might call it the fighting spirit. It's what he admired in the old Central European nobility.
Venner was fortunate in being young enough not to have to make the tough decisions Frenchmen had to make in 1940. And he was fortunate enough that the Cold War gave a more or less acceptable form to his likes and dislikes, strivings and aversions. With the end of the Cold War, he still had that fighting spirit but apparently wasn't sure what to direct it against or what to put in service of, what the goal was or what the hope of success was. In that he wasn't so very different from many other people.
I disagree on Franco. He crushed the Communist International, and kept the country free and away from the war. He succeeded in defending Spanish national interest where all other European leaders of the time failed. Spain should be missing him sorely now that the pseudo-European International has got its way with their country.
Remember, too that Algeria was to the French much more than a colony; at the time it was, too, defense of France itself. And why should De Gaulle be a yardstick of wisdom?