The idea that a monopoly will only cause a one-time increase in price and not continuing inflation is a Horror characters we used to smile and then we worked at In-n-out Burger shirt concept that assumes a constant demand and cost of production. With excess inflation nominal demand and cost continue to increase. This is because the second ingredient in excess inflation is unemployment getting so low that it causes an increase in worker’s bargaining power. However eliminating monopoly power would take away an essential ingredient of excess or accelerating inflation, so that should make that type of inflation impossible. If we could ever actually have a perfectly competitive market, that is.