That’s not how it works in practice. When a candidate wins, they’re established as a benchmark for what’s popular. This means candidates are more likely to be close to their position, but a bit left or right. This is called the “Overton Window” and it establishes what people talk about politically on the national stage.
When Trump got elected, he started expressing opinions about LGBTQ people, vaccines, etc. Everyone was then forced to argue around those points for 4 years. When Biden was elected, we started talking about unions, corporations, Israel and Palestine, etc. If you take a look at the EU, they’re talking about things like corporate gatekeepers, universal healthcare, and banning Nazi rhetoric.
By electing people who are progressively more and more to the left of the current democratic candidate, we can shift the Overton Window to begin talking about things like housing, UBI, corporate monopolies, etc. But it’s a gradual process, so we have to be persistent but accepting if it doesn’t all happen immediately.