For those who only care about getting a good meal, this is a blessing not a tragedy. But those with expectations of going to the great restaurants as their incomes rise will be frustrated by the fact that the best remain agonizingly out of reach unless they grow rich much faster than the average. So only the wealthiest of the wealthy can have these goods and must pay a growing premium to do so.
Nye’s point is that the price of positional goods will go up faster than people’s incomes. Think of Harvard as a positional good. The commenter’s claim is that the key positional goods are indicators of cultural supremacy. This would imply that the conflict between old-fashioned liberal values and the new social justice values is over positional goods and thus will be very intense.