For rich people (meaning the ~3 billion people that have some sort of access to medical infrastructure), it is a solved problem, but there are quite many people without any access to it. Even for those "solved problem" people, taking a pill every day to be protected is inconvenient. They might not take it every day, etc.
Also, even if it were a solved problem, the methodologies developed here can probably help with other viruses too in the future. This has already happened with the antivirals originally developed for HIV.
Again, inaccurate. You can get a PrEP shot twice a year now.
Access is a valid point. Perhaps the money being used to fund a superfluous vaccine should be used to fund access to PrEP in the Third World.
I was 16 when Magic Johnson announced he had AIDS. That was the first time it felt real to me. I remember a couple of friends crying because we all thought he would be dead in 1-2 years. And here he is and seems to be living a normal life.