Herd immunity means it’s effectively eradicated, meaning that enough people are protected from it that the virus cannot readily find new hosts and basically “dies out” in the areas in which herd immunity is reached. That’s why severely immunocompromised people, eho often cannot get vaccines or cannot mount a response even if they do get vaccines, do not get, e.g., polio. If only the majority didn’t get the virus, those who are susceptible (the minority) still would, but this doesn’t really happen (in places where herd immunity is reached). Other places around the world may still have the virus floating around, but after a while at the herd immunity level in a location/ country, it is effectively eradicated.

On top of what Legge said, herd immunity is for people who cannot get vaccines because of things like autoimmune diseases. who need to rely on the vast majority of people to be vaccinated to prevent the spread to them. It’s not for people who ‘just don’t like vaccines’ but have no medical reasons to avoid them