Of course they should, but they also want to sell their system to travel companies such as Orbitz, and I'm sure the likes of Orbitz wouldn't want to see advertising to their competition on the ITA site.

It's already great that they make the service available freely. It's helped me many times with either my travel agent, or with finding the cheapest airline. In the end, there tends to be a small difference, because of exchange rates or such, but overall, I've saved thousands of dollars this way.

Cheers,

GenevaFlyer