I see the vaccine like I see a oil filter. Oil laden with oxidated metal flow through the filter and not all of it is caught by the filter. However, as the oil circulates through the system, it continuously enters the filter over and over. Each time the oil is cleansed of more impurities. In the case of the virus, it goes through the human immune system. Those who have their immune system enhanced with immunity (from infection or vaccine) will “filter” out the virus. Those without immunity will allow the virus out into the system to be caught, perhaps, by those with immunity. This cycle will eventually cleanse the population of the virus.
The flaw with that is seen in how infections worked prior to mass vaccination. Smallpox - for example - existed for roughly 3,500 years. It killed over 500 million human beings in its last 100 years of existence alone.
About a decade into a worldwide mass vaccination program and smallpox was almost completely eliminated. Smallpox has since been wiped off the face of the Earth. The last recorded case was in 1978. After 3,500 years of circling the globe, slaughtering hundreds of millions of people, it was completely eradicated in basically the blink of an eye thanks to mass vaccination. It was never going away on its own. It just found new hosts to infect.