We don't really think about it much, but without plumbing, New York City wouldn't exist.
In fact, civilization wouldn't exist.
Plumbing takes years to learn, but the training is free. And there is no college tuition to worry about. Training for becoming a plumber takes place in classes in the evenings during the week. Often, people will work for a plumber during the day - getting paid - and take the free classes at night.
College is only one option for you, and it is not a requirement for success at all. Plumbers are very well paid, and if they own their own business, can become millionaires. There are plenty of job opportunities for plumbers.