Your points are very valid, although I'm kind of skeptical of someone's need to be right.

IMHO one can learn for herself or himself, however not everyone is a self-learner or a go-getter.

I started studying by myself, then I took a complete course because I thought I'd learn more at school than on my own -- I was both right and wrong because I could have learned by myself, but I am talking 25 years ago. At that time only high middle class had VCRs.

I didn't know where to get decent books and I didn't have any mentors who could lead me.

I had the great blessing of hanging around with American missionaries, that made a huge difference on how I learned English.

I persisted on my English course because I thought that to teach I would be required to display a diploma, but matter of fact I never needed it.

I don't regret the fact that I stayed at a language school for 3 and a half years; I grew and developed myself in different ways.

Not everyone is an island.