Tourism brought much wealth into the area and business sprung up to service the hotels that began to dot the landscape. Some of those tourists stayed on and built summer homes, thus the vacationers and the town seemed to enjoy a mutual prosperity. But the old guard was changing. Early in the 20th century, diesel-powered ferries replaced the whale boats while housing developments and small manufacturing firms sprang up on the sites of old farms. Like the rest of the country, Islip and all of Long Island suffered during the Stock Market Crash and the Great Depression. When the veterans returned home from World War II, there was a housing shortage in New York City, but a rebirth on Long Island. Within a decade following the end of the war, Islip began to turn from a bucolic farming community into a bustling suburb, becoming what was once described as a "bedroom" of New York City. The influx of people was tremendous - from 71,000 in 1950 to 280,000 in 1970. Then, as growth continued eastward on Long Island, the pace in Islip slowed.