Distance learning can absolutely be a substitute for college, a truth that is being borne out by the ever increasing number of accredited online colleges and universities.
One argument to the contrary is the idea that actual physical presence in class is more complete and organic. This is patently false. With the quality of many distance learning programs, students can interact with professors through e-mail quite easily. Additionally, for many college students it is easy to decide to skip class and get notes from a friend. However, distance learners are often more motivated due to the busy nature of their lives or the stakes involved in gaining more education. These folks are unlikely to skip an online lecture.
A second argument against distance learning is the lack of accountability. However, this is also clearly in error. Good distance learning programs have regular homework with deadlines and well-constructed exams. The students are responsible for mastering the material and then are held accountable for such mastery through the exams and tests that are administered regularly.
A final argument that distance learning is a poor substitute for college is that there is not enough hands-on application of the material. This is the worst argument ever. Most distance learners are gaining further education in a field they are working in. What better practicum is there? Furthermore, if the distance course is in education, they often have ways of requiring a practicum for their students.
In conclusion, distance learning is a wonderful alternative for people who have been forced to join the workforce before completing college. It is also useful because some programs are beginning to take into account the practical knowledge you bring into the experience due to your experience. This sounds to me like common sense and a truly adaptive learning environment.