I don't think he was necessarily wrong with The End Of History, (un)-ironically historical events weren't on his side. What would have replaced "The War On Terror" if 9/11 doesn't happen? What does China look like if someone less hard-liner than Xi Jinping replaced Hu Jintao? What if Russia's second war in Chechnya lasted a hard 10 years and Putin is pushed out? We could make a huge list of counterfactuals like these.

That being said, the problem with Fukuyama is that for all intents and purposes, forecasting the future in terms of grand narratives is impossible to do accurately.