Has liberalism failed?
quillette.com
quillette.com
For a much more interesting argument on the other side see Pinker's recent stuff eg https://www.youtube.com/watch?v=1s2qyYQIRQE and his latest book.
The first thing to do in going about non-futilely answering and discussing the question would be to broadly define liberalism, about which there are presumably many different definitions/ideas/understandings, to bring to light some of the presuppositions that debate would otherwise be a blind struggle over. (That's an assumption of mine.) Is it to be just 'what we have in the western democracies nowadays'? But it means different things in different regions and countries. Is it something people aspired to in the 18th C and we've not achieved, or achieved and lost, or achieved and have moved on? (In discussions of 'Has communism failed?' the huge gap between what the word meant originally and what the Soviet system became is central, and even that is not a simple question to answer. It depends which definition you use.) Maybe every system fails.
That reminds me what I was reading today in the comments on the agile theory vs reality story. Radical cool new ways of doing become their own opposite when set in stone and blindly followed. Which reminds of how in the USA the Amendments are usually touted to justify some asinine practice nothing to do in spirit with the original Amendment in any way, and more usually its opposite.
Democracy itself is hardly a total success or free of contradictions, exploits, shortcomings[0]. Depends which sense you use; there are wholly differing definitions of democracy used by the major writers/theorists of the subject.
And failed relative to what?
The shortest and quickest answer, here a good one I think, is that given by Betteridge's Law[1] — No.
But it depends.
[0] A couple of very readable and more-relevant-than-ever classics on this theme: Michels' Political Parties (1911) and Lippmann's Public Opinion (1922).
[1]https://en.wikipedia.org/wiki/Betteridge%27s_law_of_headline...