If you look at the linked report it says that online segments are growing in all of air, rail, car rentals and hotels--"vacations" are just not growing as a segment online. I think what tstegart might be saying is that it's not obvious which aspects of "vacation" are left, when all of those pieces can be booked individually.

I agree with regard to whether or not this needs to be disrupted--I do some work for a local travel agency and the level of service they provide is remarkable (it would be very difficult for me to save money by booking the same trips myself online, without even accounting for the time it would take me).