The most appropriate response is, compared to what? The authoritarian models would be Russia and China. A few rhetorical questions are in order:
- Are refugees from Africa and the Middle East lining up to get into either country?
- Has economic growth in Russia outstripped the US in recent years?
- Do Putin’s military successes in Crimea and Syria somehow make Russia a better place to live?
- Do the Russians produce anything that anyone wants to buy except petroleum products?
- Are the people of Hong Kong happy about increasing Chinese efforts to control the politics in their city?
- Would you like to live in a country that kidnaps citizens of foreign nations and holds them in secrecy?
- Would you like to live in a country that severely limits your access to foreign web sites?
- Is inequality in China increasing or decreasing?
No, liberal democracy has not failed, particularly relative to the alternatives. Individual politicians and governments, yes; the systems themselves, no.