Fame
Although swimming is a popular sport, it's no men's basketball. You won't have the same opportunities for seven-figure salaries and reality TV shows. The most competitive meet in collegiate swimming is the NCAA Division I Swimming and Diving Championships.
Even cooler than the NCAA Championships (or anything, really) are the Olympics. Swimmers are eligible to go to the Olympics during their college years and many do...though the average Olympic swimmer is older today than in 1984 (source). Qualifying for the Olympic team and earning an Olympic medal are still considered the heights of fame for this sport.
Cue the papa-paparazzi.
Unfortunately for swimmers' bank accounts, they lose their amateur status (and, therefore, their NCAA eligibility) if they accept sponsorship deals (source).
Still, many swimmers do choose to turn down deals so that they can continue—or begin—training with a college team.
After graduation, top swimmers can qualify for the National Team, where they continue training in hopes of qualifying for the Olympics or competing on the professional circuit. Here, they're allowed to scoop up sponsorship deals and take home prize money for winning meets. Hey, Nike—about that offer…