The industry owes much of its early success to the popular TV show "Love Boat". For nine years (1977-1986), Love Boat inspired mass-market travelers to go on a cruise vacation. Most previously thought that cruises were only for the rich and famous.
Most 19th century steerage-class immigrants heading from Europe on ocean liners to the Americas had deplorably dark and damp barrack-style accommodations. And the food served was awful.
War time effect
Some ocean liners were requisitioned by the government and converted into troop carriers and floating hospitals. Severe overcrowding was an issue (I know because I crossed the Atlantic as a soldier on a sardine-packed ship). A few converted ships didn't make it - they were torpedoed or mined.
American shipyards once played a key role in cruise ship construction. Today, nearly all the major major cruise ships are built in Europe. Japan is the second leading builder.
Through the years, cruise ships have grown in passenger capacity. Today, the Oasis of the Seas and the Allure of the Seas can each carry 8680 people (6,296 passengers and 2,384 crew members). That total exceeds the populations of the home towns of some of the passengers on those ships.
Cruise revenues (currently around $30 billion dollars annually) and passenger count (19 million per year) are expected to rise. The future looks bright.