Travel agents don't always have the best options. I traveled on 5 continents this year, taking 30 flights total. My total cost of flights was also about 7k, compared to the author's same cost for half the flights. I booked everything separately, using Kayak, Hipmunk, and local airline offices in Nepal, Fiji, and Jordan. If you research travel hacking and follow those tips, you can find great deals.
The main bonus for me was the freedom to fly where I chose, rather than where the airline offering the RTW ticket.
No, but its important not to rule it out entirely, which is attitude I used to have, which I have since changed.
Agents often allow full flexibility by cancelling flights and crediting them to a new flight, allowing a lot more freedom than the independent route.
I know I saved a lot of money and was able to double my time in South America purely because I booked through an agent. It costs an extra $100 USD at the time but I changed the flights 4 separate times to extend dates, change destinations.. well worth it in that regard
The main bonus for me was the freedom to fly where I chose, rather than where the airline offering the RTW ticket.