Q&A: How Do Schools Decide to Offer a Class Online?
That's a complicated question, and the most honest answer is, it depends.
If a school is mainly a traditional school, with a well-established array of face to face classes, they are likely to add online classes only if and as individual faculty members want to. If a faculty member sees a need for a class, he or she will propose creating an online class. This need might be from the school's point of view, or from the discipline's. For example, a class about how rhetoric and identity change online would be a logical choice for an online class. At these schools, you see an uneven array of online classes.
If a school is mainly a traditional school, but is having scheduling issues (not enough seats, not enough classrooms, too many requests for the same time slots, etc.), they'll develop online versions of the most commonly taught classes. If these schools are smart, they'll limit themselves to just classes that work well online: composition, introduction to business, history, etc. They'll stay away from more dubious choices, like public speaking. (Yes, it is offered online, but it really isn't the same to talk to a camera or an auditorium of 400 people.)
Colleges that are fully committed to online programs develop their courses more methodically. They develop courses based on market need and student requests. Schools that are exclusively online may enlist experts in both subject matter and design. They'll make sure the courses are part of a series and that the work load is roughly standard for the other online classes.
There are pros and cons to attending both online and on-campus classes, regardless of the school. You may get the most consistent online classes at an online school, but the most adventurous online classes at a brick-and-mortar institution.