A Wells-Fargo analyst thinks so. From the Winston-Salem Journal:

A leading tobacco analyst said Monday there is increasing evidence that adult consumers may be tapering off their initial enthusiasm for electronic cigarettes, which could limit their potential for benefiting public health.

Bonnie Herzog, with Wells Fargo Securities, said her second-quarter retailer survey found “moderating vapor category growth, with several consumers being disillusioned by e-cigs, switching back to combustible cigs.”

More here.