Yes, it's impossible to produce, distribute and vaccinate eight billion people for a virus that mutates every few months and one that can persist in animal reservoirs.
The corona's spike protein though is a simple structure that will likely still infect (be able to get inside a cell) after many kinds of mutations - some of which won't be mitigated with previous vaccinations (mu is leaning this way).
Contrast this with polio which has a Tetris like key that must link up with complex cellular proteins in our cells to enter. Slight mutations in this render it unable to pass through the cell wall. It's why vaccinating for this is so effective and long lived.
It also depends how many months have elapsed since your last shot, more than five and it seems to be waning in Israel.
With, mu early indications seem to point towards it not working to reduce severity.
That question has been asked and answered ad nauseum, it's a resounding yes, especially for the mRNA vaccines.