The average person just doesnt care about things as long as they are placated and their most base needs are met. Many people actively avoid or are angered by having to think for themselves (see the “its not that deep” crowd).

You end up with

1. a large non voting population that just listens and passively supports whatever the most popular ideas are
2. a small but vocal, fervent minority that drowns out everyone else and is backed by corporate interests. Typically these corporate interests are able to pay people to advocate for whatever they want, bribe politicians, whatever.
3. A minority of people who tend to actually think for themselves, have more empathy / be less individualistic but have their voices, ideas and causes suppressed by the people in 2.

In the US, republicans are 2. and Democrats try to appeal to 2 since theyre paid by those same corporate interests when their voting base is actually 1. This leads to people in 1 who would otherwise have voted for them feeling like theyre unheard since the democratic rhetoric either appeals to 2 or denies the realities and actual popular ideas

Add on top of that capitalistic pressures on the average working person and people tend to become more selfish and individualistic, which causes ppl in 1. to just not vote if the democrats dont give them what they want, 2. to always vote republican because they fall for the propaganda, and 3. to either vote Democrat anyways as harm reduction or not vote because the Dems dont listen.

Really, it is the apathy of the more “left” party to what people actually want that pushes people towards anyone who will listen, which tends to be the more “right” party that will try to activate any fear they can and promise people the moon just to get a vote, even if they never have an intention on delivering.