Having a good treatment and having vaccines are certainly not mutually exclusive. Would you want to take a chance on getting, for instance, a highly contagious form of polio, on the theory that you might not die or lose the use of your legs because you could get a treatment that works for a lot of people (but maybe not you)?

Vaccine companies will still sell lots of vaccines. There will still be lots of people who don't or can't get vaccinated, who need treatments.