All of the reasons why.
The biggest threat to the future of the aircraft carrier lies not in missiles or torpedoes, but in the enormous combined cost of the ships, their escorts, and their air wings. This is a problem that has not improved over the past century; carriers have grown ever more expensive, increasing the strain on defense budgets and national governments.
HMS Furious, the first real aircraft carrier, entered service in early 1918. A converted cruiser, she displaced about 20,000 tons, and flew about half a dozen Sopwith Camels, an aircraft with a range of about 150 miles and a weapons payload just short of 100 pounds. Twenty-five years later, Furious could carry 36 aircraft, ranging at least twice as far with weapon loads of around 2,000 pounds. Her larger, purpose built cousins could carry double the number of aircraft. Armored flight decks, improved anti-aircraft armament, and better damage control procedures protected many of these later carriers from attacks that would sink their older brethren.