It does become complicated when the scarce inputs are things like highly specialized labor. Georgism wouldn't tax that monopoly, though our current systems (progressive income taxes) do. Many people would want a system which penalizes businesses for buying up e.g. all the veterinarians in a city and charging monopoly prices.
Taxing specialized labor goes against that spirit, because specialized labor can be created. And in fact taxing the labor would result in less of it being there, the exact opposite of the optimal result.
Do you have a source on this?
What's the definition of this term?
I think people get tripped up on this specifically because a growing demand for something with fixed/inelastic supply will naturally tend to cause that thing to become scarce given enough time, and it's that scarcity as applied to land that's making Georgism look more and more like a good idea.
As powerful as taxes are to create change, you don't need to use them to solve every problem out there.
Although, maintaining a monopoly by owning land becomes more difficult with a LVT. It theoretically becomes easier for a new vet to find a place and setup shop in the city, and then the Monopoly is busted.
What if they just moved? Or should we have US-style global taxes following them around even then?
If you buy company x, restructure the business, start turning a profit, then sell the company -> that income (capital gains under current system) is untaxed in Georgism
If you buy an empty lot, wait 10 years to sell it to someone at a higher price, then all that profit is taxed (before it is realized too).