It's definitely not uncommon.

I think it's more of a motivation problem. Not all students are eager to learn. They may not be interested in the subject for whatever reason. It's hard to teach someone who isn't open to it. Learning styles can help bring some of those barriers down by shifting the material into a form that they are more open to.

The same applies to building muscle. Not everyone is self-motivated to do it. There are different ways to motivate people to work out. But in the end they all need to do the work/practice.