Just the wrong questions being asked
Mr Worstall first argues, somewhat correctly, that Walmart creates value to the American retail business. It is clear to anybody that large distributors can be a lot more efficient than the local grocery. Still, their monopsonistic business practices are well documented and are causes of concerns.
Then the author puts an equal sign between the fairness of the company to earn 3% of $136b / year (fine with me) and the fairness of 4 individuals to own 50% of the company shares, when the company employs 2.2 MILLION people. They had 50% when the company was 100 people big, and they still have 50% when the company got to 22,000 (00s) people. Is their contribution to the company 250,000 times larger than another employee's? Who can argue that in good faith? Fixed equity is the cornerstone of inequality. It is absurd to measure their contribution to the company using a measure 50 years old.
And, most probably, they also inherited this fortune by paying a pittance in tax. Inheritance tax should be exactly the same, if not larger, to normal income tax.