There are three main reasons why ships were scrapped quickly. The first is that new ships building towards the end of the war were more suitable replacements. Most of the ships built before the war had been used hard during the war. They had sustained damage, seen maintenance and refits deferred, and often lacked new technologies. As an example, the British carrier Illustrious (a contemporary of Enterprise) had the propeller removed from one of her shafts, dropping her speed to 24 knots, in 1945. This was because that shaft had severe vibration issues caused by bomb damage sustained in the Mediterranean and Pacific, exacerbated by the quick fixes taken to get her back into the action as soon as possible. While these issues were rectified in the immediate post-war period, vibration issues returned on her other two shafts. As fixing these problems and upgrading her to take modern aircraft would cost almost as much as buying a new carrier, the RN chose to scrap her.

It was easier and cheaper to upgrade more modern ships to take new technologies. Illustrious' half-sisters, Implacable and Indefatigable, had hangars that were too cramped and weak to carry the large, heavy new aircraft that were expected to enter service in the next few years. As with Illustrious, upgrading these ships would cost a significant amount. Only one Illustrious-class carrier was modernised, Victorious. Her reconstruction cost ~£30,000,000 in 1953 pounds, just under three times as much as it took to upgrade the newer Eagle to a similar standard - though it must be noted that part of this was down to poor project management. Scrapping older ships, and moving to newer ships, meant that navies could increase their capabilities. Navies had to make choices like these because of the rapid demobilisation that followed the war. In 1944, the RN had some 800,000 men and 73,000 women in uniform. By 1950, these numbers had dropped rapidly, to 137,500 men and women. While peacetime complements aboard ship were lower than wartime ones, it should be clear that the RN could only operate ~20% of its wartime fleet.

Economic concerns were also important. Operating ships was expensive, while scrapping them could raise money and put materials into the economy. Let's look at the British ship-breaking industry following WWII. This was handled by a government body called the British Iron & Steel Corporation (Salvage) Ltd or BISCO, which also handled the supply of other raw materials to the steel industry. Ships the Admiralty no longer needed were handed over to BISCO. BISCO would then assign the ship to a suitable breaker's yard, where the ship would be scrapped. Following this, the scrap would be sold, the costs of the demolition returned to the breaker and the remainder of the money returned to the Government. This brought in a lot of money- in 1945 pounds, scrapping a battleship would bring in £450,000, while scrapping a destroyer would bring in £30,000 ($26,000,000 and $2,000,000 respectively today). You also need to factor in the reduced costs to the Admiralty, as there was no longer a need to man or maintain the scrapped ship. This also produced a lot of scrap. Annual output from the British ship-breaking industry was about 500,000 tons, or about 3% of the output of the British steel industry. For a nation like Britain, whose industry had been devastated by the war, and which owed the US and Canada £3.8 billion (again in 1945 pounds), this was an attractive option to increase revenue and rebuild their industry.

Enterprise was already obsolete by the end of the war. She had been designed while the Washington Treaty was still in force, which limited her displacement. Carrier aircraft had become much larger and heavier during the war, and Enterprise wasn't designed to handle them.

The 24 Essex class carriers were larger and heavier, with a design change in the later ones increasing their size and length even further. The Midway class carriers which were under construction were even bigger, with an armored flight deck and numerous other improvements from lessons learned during the war. Both designs would serve through the Vietnam War.