"The ongoing loss of life and health due to HIV could be stopped if we cared enough to invest resources in wide-scale PrEP availability and public health education."
It wouldn't be stopped, only slowed. You would still have transmission from accidental or unknown exposure. You would also have a small portion of the population that didn't care, regardless of the education.
As we all hopefully learnt from COVID-19, slowing sufficiently is the same as stopping. It’s a numbers game. Slowing transmission below some threshold will eventually mean that there are no new transmissions.