Here's another thing to think about and why if(and this is the world'd largest if 🙄 )a completely 100% effective anti caries vaccine is made(extreme laughter please)that atleast 1 more generation of dentists will be needed(and this doesn't include trauma, cosmetic, and pathological reasons for dentists). All of the BILLIONS of existing restorations only have a finite life span and will need replacing at some point. Also, over time the vast majority of sealants placed will also need replacement.
In my own opinion, with the dietary trend of the US population as a whole in terms of a generalized increase in sugar consumption, caries is and will continue to be a big problem (remember a 20 oz bottle of mountain dew has 19 tsp. of sugar). Also, if it is an anti-caries vaccine, the same love of injections that keeps many folks away from the dentist office will keep folks from getting the vaccine. Strep Mutans will be around and continue to prosper for atleast another generation of people 😉 😉