No. The earth doesn't get flat no matter how much people you get to believe it. As for opinions, they're still just opinions. There's no right and wrong opinion.
Nothing matters to reality. "Mattering" is a human judgement. "Fact" is also a human judgement. The things you have in your head that you call facts and opinions are both the same kind of thing. We consider the ones that model reality effectively to be facts. They are all opinions and discerning which we classify as facts is an ongoing process.
I did not say opinions are fact. And I am not saying that opinions change reality. But your assertions about what facts and opinions are is incorrect.
Ehen we're going into the more abstract discussion of facts and opinions, it might be better to define how you're using these terms rather than throw accusations.
Most people define fact as "a thing that is true". And opinion as "how one feels about something".
Personally I prefer to use fact as "a statement that can be checked". But in every day conversation like here, I don't. Because that would just confuse most people.
Jerry was home schooled by his uncle, and has been told the earth is flat, and concluded the earth is flat.
Jerry is wrong. When Jerry tells his friends the earth is flat, he is not lying. Just wrong.
When Bob says the earth is flat, he is lying. Knowing full well it is round.
Jane was taught that the earth is stretched a little bit because of the centrifugal force of it's spinning.
Jane is also right.
Bob and Jane had a conversation about the shape, and experienced a thing called nuance. It's not perfectly round after all.
Yes. If, back when people believed incorrectly the earth was flat, someone played a joke on Cob and told him the earth was really round and he believed it, he's correct too. Even though someone manipulated him into believing something they themselves didn't believe.