I always tell people: "I don't sell flights, there are a thousand websites that do that. I sell service".
Guess who else serves the same "service"? Expedia, travelocity, each airline....in other words the "thousand web sites". I have yet to see on this entire thread what "service" a TA provides that isn't also provided by all of these competing service providers? Guess what TA's, you're one of the thousands of service providers, so you've got to provide services they don't!
On the other hand, I can tell you what "services" that these competing suppliers provide that in my experience TAs don't:
-Instant confirmation of your flight online and by email.
-24 hour access to make bookings and changes, from seats to flights.
-No additional fee.
-The same price or lower, especially when taking into account a fee.
-More intuitive view of choices and a greater number of choices (of routing, times, airlines, layovers....) I can look at a grid on ITA and or google flights and better see in 30 seconds what would take a TA 10 minutes to explain over the phone.
I was a government employee and had to book all business flights through our contract travel agent, SATO or Carlson Wagonlit depending who had the contract. My job involved flying small aircraft around the country and taking a commercial flight at the beginning, end, or both of the delivery, so I flew a lot with a lot of last minute changes, something where a TA should shine. They had a rudimentary online booking engine which was expedia circa 1999, and even it was light years ahead of any agent I spoke to. And we paid something like $40 every time we talked to an agent, even if the agent was worthless, which they were 100% of the time, as well as something like $20 for the privilege of using the online booking engine, which again was archaic. The sad thing was that GSA did all the heavy lifting of bidding out contract fares, so the travel agency was literally doing nothing but booking flights and they were 10X harder to use than any of the commercial booking engines. So anyone who says a corporate travel department should value a TA clearly hasn't had to live through working with a corporate contract TA!