Seems weirdly selective to point to "over time it is 0%" ... well yes, I assume that if I never get another vaccination that at some point in time I may be susceptible to COVID.
What this study does show is that with a booster shot you are offered significant immunity against COVID, including omicron. I'll take 50 or 60% over 0% any day of the week.
I am incredibly grateful for the vaccines, which have done (and continue to do) a tremendous amount of heavy lifting as far as global health and reducing severe illness and hospitalization is concerned, despite those who like to pretend that they are pretty much useless.