Question

"in terms of dollars spent, direct mail is the second largest promotional medium (after television). what is a major disadvantage of direct mail?"

Answer 1

A major disadvantage of the direct mail would be the cost.
Direct mail tend to need personalised copywriters, artists, and photographers for its making in order to make it more interactive.
And considering that most direct mail ended up with low response, the expense that you put for the making may not ba able to be turned into profit.