> How do you determine the value of intellectual property if not by looking at how much income is actually being derived from said IP?

I agree that determining the value of IP is difficult. Georgists would probably advocate that there is no reason for IP to be in private hands in the first place, nor any need for a system of IP.

Alternatively, you could give temporary ownership of the IP to the creator (like we already do, except without the absurd lengths of time), then when that expires, put it up for auction to determine the pricing, then tax based on that.

You hold an annual auction for the exclusive rights to the property that the tax will be derived from. The current owner can choose to keep the rights and pay the tax or they can choose to sell the exclusive rights to the highest bidder who must pay and then becomes the holder of the exclusive use rights and the new owner would then also pay the tax based on the known value.

This might also usher out IP trolls and IP squatters.