The data is still forthcoming, but the fact that the reinfected vaccinated people and vaccinated with booster are only experiencing mild symptoms is a sign that the vaccine is still working. Immunity isn't a dual state of yes or no, but degrees. So if a variant truly evades the vaccine, what we'll see is not just vaccinated people getting infected but getting sick enough to be hospitalized and die. That hasn't happened so far for people who have still "robust" immune systems. That robustness, btw, explains why it's the elderly who have mostly died from COVID, even fully vaccinated elderly. Declining vaccine efficacy may also be a contributing factor. Your immune system just isn't as strong in your mid 60s and older compared to younger (taking into consideration other factors like congenital immunodeficiencies, deliberate suppression from organ transplantation or acquired immunodeficiency like HIV infection).
Finally, the continued focus on older people dying from COVID misses so much. I'm fine with not spending weeks in a hospital bed just to stay alive when prevention is easier. Plus, there are previously healthy people in their 40s and younger (so not 85) that can't go back to work because of long COVID. I also came across something this week that people who fought a bout of COVID severe enough for hospitalization have a higher risk of dying within the next year.
New research finds that people with long COVID have twice the chance of dying in the next year than those who never developed COVID-19.
www.healthline.com
So to focus on death and age of the people dying is a very incomplete picture.
(Btw, I really appreciate that this thread is mostly full of sensible people).