score:3
I was just able to get ITA Matrix to price out the exact itinerary you want, but it also costs $3,103.66:
(There are a couple of different ways to get to Naples with this, but most are similar in price.)
The reason for the fare difference appears to be the difference in availability in fare classes. Your friend's itinerary can be booked in fare classes N and V, which American uses for some of its cheaper economy fares. The flights to Naples are pricing out in H class, some of their more expensive economy fares.
Sadly, a one-way flight from Rome to Austin on your friend's itinerary is pricing at $2,246. I was thinking you might do that and then grab a $600 Condor flight from Austin to Naples, but you'd still be coming in at around $3K that way.
If you're able to fly out on the 16th instead, you could do this for about $1,300, but note the change of airport in London:
Upvote:2
I just don't understand why I'm not being presented with the same options.
The simple answer is that the fare buckets for the itinerary that your friend has purchased may have been exhausted by the time you started your searches - there are only so many fares available in given classes for given routings.
There is also the airlines own yield management tactics to consider. Airline pricing and routing management is complex, and if the airline wants to improve a particular route yield (either the revenue generated by that route or the passenger count on that route, depending on the metric the airline is using at the time) then they will simply not offer alternatives in order to push you onto a given routing.
The only thing to suggest at this point is to actually call American Airlines and speak to one of their booking agents, explain the situation and ask them if they can put you on a specific routing. You may be in luck and they may simply have the routing blocked out in the automated ticketing system, but available to the booking agents.
Or the route may be sold out.