You are assuming a static virus-host interaction. It's not a static system, it's dynamic. The virus is evolving to escape vaccine-induced immunity because that immunity is narrow and very similar across all vaccinated individuals. Newer variants are better at infecting and reinfecting vaccinated individuals. These individuals are poorly able to improve their immunity due to immune imprinting/OAS.

You are assuming a static virus-host interaction. It's not a static system, it's dynamic. The virus is evolving to escape vaccine-induced immunity because that immunity is narrow and very similar across all vaccinated individuals. Newer variants are better at infecting and reinfecting vaccinated individuals. These individuals are not able to improve their immunity due to immune imprinting/OAS.