This is it, you're not likely to convince the person you're arguing with (*), but you can convince lurkers.

*You won't convince them then, they're too prideful and defensive to accept alternate ideas during the argument. But you might plant a seed of doubt. Overtime, it might grow and and be accompanied by other doubty plants from seeds planted by others along the way, and who knows? They might have a breakthrough someday, and that argument, perhaps from years ago, was a part of it. I've been on both sides of this dynamic myself online and in person.