I learned at an IATA course that the revenue management (RM) software industry is dominated by a consulting firm in Houston called PROS -- http://www.prospricing.com/

The class also provided some statistics on how well it does. On a single nonstop segment, RM improves revenue by 6-8%. But on multi-segment trips, because the additional combinatorial complexity makes the challenge much, much harder, RM only improves revenue by 0.25-0.5%!

All that staff, all that fare variability, all that computer software -- just for 1/4-1/2%!