As a 9-year dispatch veteran, let me break it down for you:
Big costs for the center is technology. Computer-Aided Dispatch (CAD) Systems can easily go for $1 million, this allows the computer integration you spoke of. The CAD system may be a one-time purchase, but like all technology it has to be maintained and upgraded periodically to keep operational. Factor in IT costs, and regular equipment replacement (broken keyboards, bad monitors, etc).

Many centers, including those in Anchorage are not 8-hr a day jobs, they work 4x10s designed to give a surge of people during the busiest hours of the day. This also is important to prevent burn out by giving them longer weekends, which studies of the field has shown is vital to preventing burnout or worse, substance abuse or suicides.

Anchorage maintains 2 centers, one at APD and one at AFD that perform vital and different missions. A third site at the city EOC is also maintained for disasters where one center is unusable.