It sounds like the argument is that voters are rational and therefore must vote for the correct level of LVT. Doesn’t the evidence show that the ideal LVT rate is zero, since that’s what they have in fact enacted?
Whether this theorem is robust against systematic cognitive biases is another matter. I don't know the answer to that, but it seems like voters are more likely to eg. vote for a tax that falls on someone else but gets passed along to them as higher prices, which would be an argument against an LVT ever being enacted.
Also, elsewhere in these comments are good arguments why an LVT is very difficult to "bolt onto" and enact a government once it's already been formed, which may be why we don't have one. That's simple path-dependence: Georgism didn't exist when most modern industrial nations were first formed, therefore it can't exist now.
This, incidentally, is the function of propaganda. You introduce an influence that biases the system to encourage certain classes or error and discourage others, thus skewing the consensus-forming process.