Ok, using your example, if we invented commercially sold personal spacecraft vehicles tomorrow after a few years of research, would you be the first to ride and adopt that new technology? Maybe you’re brave enough but many would rightfully say “woah. That’s some new tech and if they didn’t work out all the kinks, I could die in space”. They might wait and see, and is that really such an irrational decision. But let’s say you take the plunge and ride it. You have tons of fun. And when you read the research, you find that it’s actually been 20 years since they started the development, and recently had a breakthrough. You could then tell friends and family; hey! It’s safe and fun! And it’s actually been in the works for this many years! Some may then decide to buy one too. Humans are slow to change sometimes especially when it involves their health, even if it’s an irrational concern. Now, if after educating someone about vaccine benefits, they still remain stubborn. Well at that point you’ve done what you could.