@clintflint - It probably depends on what kind of animation we're talking about. If you consider claymation to be animation, for example, that's something I think can be picked up outside the classroom. There's also the question of what aspect of animation someone wants to pursue. Are they interested in character creation? Because that's not really the same thing as developing ways to make animated hair flow properly.
I actually think it's worth taking a course, just because the field is so complex and extensive these days it would be difficult to navigate on your own. But there are definitely still people who manage to crack into the industry without going through school first. They teach themselves and then they make their own creations as examples of what they can do. There are decent games out there created entirely by one person, and plenty of short animated films as well.