Bad economies can help populist candidates win elections. When people's lives are hard, they may choose someone who promises big changes, even if that candidate has been less successful.
Populists like Donald Trump can be popular even when the economy is doing fine. Many voters don't rely on economic indicators and instead follow narratives that make them feel understood.
Good economic governance might not be enough for traditional parties to win against populists. They need to connect with voters on a personal level and address their feelings about the elites and the current system.