Well most people can't prove the earth is round in any meaningful way, so why not think its flat,
Really doesn't matter to most peoples daily lives
But just for the record a Flat earth is a fairly new concept.
Prior to any scientific evidence, anyone who cared to think about the earth as a whole, thought it was round, especially if they ever climbed a higher hill or were near a large body of water
You can see the earth's curve
Our forefathers were ignorant not stupid, lol, so for anyone who cared about it, the earth was round.
And No, Columbus and the sailors aboard with him did NOT think the earth was flat, but they didn't know how far it was to the next land fall for food and water, and that was the scary part
Eratosthenes of Greece wrote it all down in around 200BC, so like most things, the earth being round was known much earlier just written down for the record in 200BC
He calculated the circumference of the earth and was pretty close considering he used a short baseline for the calculations.
But to most people its one of those things like Gravity, why would you even need to write it down, lol, you can SEE the earth is curved, same as you can SEE gravity at work, or feel it when you trip and fall
Isaac Newton and the apple, you really think people didn't know about gravity before that..................
To most people at the time it was a waste of paper/papyrus to write it down, but most couldn't read in any case, lol.
There are people who think Gravity is not what we think it is, for example: when you drop a ball the ball doesn't fall, the earth expands out and meets the ball
The earth/universe is expanding constantly, as we are, and thats what holds us on the surface, and thats what gives us the "illusion" of gravity
Flat Earth, no Gravity, hey it is all just good fun, until someone loses an eye
Never run holding scissors