The thing is, the Earth’s not a sphere either, it’s an oblate spheroid because it bulges in the middle. They were wrong about that. Oh wait, they were wrong about the oblate spheroid too, it’s actually also slightly pear shaped, with the entire northern hemisphere being a little smaller than the southern one. But see, those facts in succession, even the very first one, highlight something really important about this question: if you asked the average member of the public about the shape of the Earth, they’d say it was round. Not a perish oblate spheroid. ‘Average public knowledge changes’ is very different from ‘a scientific truth is debunked’.
I honestly don’t think we’re ever going to see something in hard science debunked in a way that has a big impression on public consciousness.