There are people that believe in flat-earth. Not entirely sure why it persists.

There's a difference of holding firm in one's existing belief/understanding and not just changing the beliefs as the winds change, but only with strong compelling evidence. It's entirely different when that evidence is presented in multiple forms and yet one still chooses to ignore it.

Flat-earthers are very few. You only really see them on social media where rage bait and fake stupidity get engagement.