I mean the moon has to have some effect, right? Given the effect it has on the oceans, it must have some effect on a liquid core as well. It's actually surprising that it's not the number one suspect for causing/ generating Earth's magnetic field (whatever the mechanism) when you consider that Earth is the planet with both the relative largest magnetic field in the solar system, and the relative largest moon. Not to mention, most of the planet's surface is covered by an electrolyte.

If both Mars and Venus have liquid cores and not much in the way of a magnetic field, it seems like there must be more to it, and it's likely to be one (or a combination) of factors that makes Earth unique in the solar system.