Monoclonal-antibody therapy is not unique to COVID. Barry, forgive me if you already understand this, but in case you don't, monoclonal-antibody production mimics in a "test tube" what your body does naturally when your body produces antibodies to battle an infection in your body. Basically, taking the vaccine does the same thing in your body (produce antibodies) that monoclonal-antibody production does in a lab.
Problem is that monoclonal-antibodies are very expensive to produce and cumbersome to administer (one has to be in a hospital and infuse the monoclonal-antibodies into your system). You'd have to be crazy to refuse to take the vaccine thinking that if you get COVID they could treat you with a monoclonal-antibody therapy.
OTOH, if you happen to be someone who has not yet been protected by the vaccine, and you get COVID, then monoclonal-antibody therapy would be a good option for you since the vaccine is then nearly useless to you; however, you need to get the monoclonal-antibody therapy early enough, you have to be in the hospital, and you have to be able to afford it. Basically, the vaccines have obsoleted this monoclonal-antibody therapy unless you catch COVID before you get vaccinated or you can't tolerate the vaccine for some reason.