The point isn’t whether it works or not - the point is why it comes to be in the first place - why and how people reach a point at which they embrace it.
And that’s when they come to see that their government is failing them - most often, when it’s serving its own interests and the interests of a wealthy few rather than the interests of the people at large.
And here’s a tip - you can’t combat it by deriding the people who embrace it. If anything, that just makes them double down on it, since, to them, that’s just further evidence that you’re an elitist piece of shit who doesn’t care about them or their needs, so they’re going to turn to these other people over here who (say they) do.
Again, there’s one and only one way to counter populism - governmental reform. The problem is that people see that the government isn’t doing enough to serve their needs. The solution is for the government to do more to serve their needs.