That's a question that will be hanging out there for awhile for a number of reasons. I posted the link you responded to to dispel Maher's notion the boosters are worthless. They are not worthless.
Here's another study.
Now possibly T and B cells are nearly as effective with two doses as with three against omicron and that's two dose vaxxed are not dying like the unvaxxed. But Maher doesn't know that. I do know that the history of this pandemic has show that those that want to "do their own research" haven't faired nearly as well as those that have stuck to listening to credible scientists.
How many vaxs are going to be needed? I don't know. Would Maher stop the Hep B series, or the rabies series at two? Evidently. Would he be adequately protected? Doubtful.
I'm also trying to wrap my head around the logic of a guy who already had two doses but is now hesitant about the booster. He almost makes a full-blown antivaxxer seem sensible in comparison.