It's hard to reconcile that all progress depends on believing we can do better than something that exists today — that what we have now isn't perfect, there are flaws, advances to make. I think that's what makes Elon Musk such a great inventor.
But all progress also depends on someone being able to show that they can make improvements. Anyone can point out that air travel isn't safe, but the people who really matter are the ones who make it safer.
Anyone can point out that, like air travel, vaccines aren't perfectly safe. But I think the ones we should listen to are the ones who either improve their safety or come up with something better. I don't think the ones we should listen to are the ones who propose that because jets crash we should drive instead. That takes us backwards in safety.