But, actually, the idea is way older than Henry George. In fact, the single tax is what the "laissez faire" economists were actually advocating. The aristocrats asked them "how can we help the economy by raising and lowering various taxes if there is only one tax," to which the economists responded, "laissez faire".
But, we never hear about "the land issue" for obvious reasons. Look who owns and controls everything. Landed interests. The ecosystem and poor people have no lobbyists to represent them. They have no money and no influence.