Real life selling skills isn't something taught in school .Why then are paper qualifications a must in most sales jobs adverts?

Selling is not something where you go selling1 product to customer and when deal is clinch, we are happy about it.

Selling has grown much more than this in recent times. It has taken a form of several steps of marketing. Professionalism came into place where you need to treat your customer delicately with utmost importance.

After sale service is something by which you can bind the customer with company/you forever.