Las Vegas has so many casinos because Nevada legalized gambling statewide, and it did so early. It was also the birthplace of hotel-casinos, which made gambling vacations popular and easy.
Today, Nevada is one of only two states that have legalized gambling statewide, the other being Louisiana.
Ten years after gambling was made legal in Las Vegas, the first-ever hotel-casino opened in 1941.
Since casinos are a huge draw in Las Vegas, people come there specifically to gamble and enjoy the convenience of a casino and hotel in one.