Why booking airline tickets is always so painful?

Goal: to buy a ticket to Chicago, 24[25] - 30 [afternoon] September, cost < $900.

List of agencies: Star Travel Авантик.сру Авиабилеты.ру Infinity TravelSelect TraveloCity

There is ~200 different routes to Chicago from Moscow.

Total time spent: ~4 hours.

Upd.: our travel agent sent a quite cheap itinerary, but for the flight to San-Francisco.

Upd.: booked in Мострансагенство.