I am not sure this analogy illuminates differences in productivity and resulting inequality as described. If everyone on earth had the same equal piece of land then it can be argued that the tax rate (as property taxes are) would not be on the income but fixed on the basis of the size of the land. So whatever Bob gets out of his land he would pay the same fixed amount of tax that Tom does.
But in the real world we are not born equal and we do not have access to the same size of 'land'. There are differences, sometime vast in family wealth, property, health care, education and access to nearly 'n' number of resources. Bob may be born with the land and have 'n' amount of time and the luxury to think of things like productivity, wealth, interests, life while Tom may struggle his entire life just to survive or maybe work towards getting 1/10 of the land as his entire life goal.
Moving to the real world property taxes are not fixed on income. Income tax is an entirely different tax that Bob and Tom would pay based on their income irrespective of their land holdings. If Bob is more productive he would pay more tax but I am not sure income tax or 'simple productivity' as a concept is useful to understand or explain inequality and disparity in a world where everyone does not have the same piece of land.
But in the real world we are not born equal and we do not have access to the same size of 'land'. There are differences, sometime vast in family wealth, property, health care, education and access to nearly 'n' number of resources. Bob may be born with the land and have 'n' amount of time and the luxury to think of things like productivity, wealth, interests, life while Tom may struggle his entire life just to survive or maybe work towards getting 1/10 of the land as his entire life goal.
Moving to the real world property taxes are not fixed on income. Income tax is an entirely different tax that Bob and Tom would pay based on their income irrespective of their land holdings. If Bob is more productive he would pay more tax but I am not sure income tax or 'simple productivity' as a concept is useful to understand or explain inequality and disparity in a world where everyone does not have the same piece of land.