The U.S. Navy has been trying to reduce its personnel strength for the last decade, partly to adjust to greater use of automation, and partly to save money to buy more ships. It costs over $100,000 per sailor per year, and warships cost 5-10 times more than they did before World War II, even after adjusting for inflation. Curiously enough, back then the navy had about as many ships as it did today, but about 70 percent fewer personnel, and a much smaller budget. So comparisons are difficult, unless you understand what has changed. And a lot has changed.
Between 1923 and 1935 the U.S. Navy fleet, which varied from 300 to 350 ships, had a personnel strength that ranged from a high of about 95,900 (officers and enlisted) in 1924 to a low of about 89,200 in 1933, arguably the most "peaceful" years of the twentieth century. During this period, there were only about 10,000 officers, of whom about 7,500-8,000 were "line" officers. Officers might expect to make captain in 25-30 years. Since then, the rules have changed, so that today, if you don't make it by 25 you're forced to retire.
After 1933, as rearmament for World War II began, numbers rose, reaching nearly 210,000 navy personnel in 1940. By then, the fleet had reached well over 400 ships. Moreover, by 1940 about 20 percent of personnel were in aviation. Big changes occurred during World War II, with the navy getting a lot more money, and new technology than it had ever seen in its history.
Today the Navy still has about 300 ships (counting the USNS, non-commissioned support ships owned by the navy, which would have been counted back when), but has about 330,000 personnel. This includes 53,000 officers, something like half or more are in the various medical/dental/admin branches.
The Navy's boosters protest personnel reductions, but have not properly addressed the question of what are all those officers and enlisted personnel doing. What they are doing is taking care of technology that did not exist 70 years ago, and providing services (medical, social and administrative) that either did not exist back then, or are now considered essential to attract and retain personnel.