The Bloomberg Terminal costs $27,660 a year (or $24k a year per user), and it's difficult to disrupt because most users are attracted by the built-in "social network" and access to a lot of premium data and features in one place.
You have to remember those terminals are used by people who earn USD1M+ with bonuses. Which in turn means that they have to make their employer at least USD10M+ per person. Their expense accounts for entertaining clients, in a month exceeds the annual cost for the Bloomberg terminal.
lol I don't mean to be dismissive but that's not necessarily true. A lot of people have bbg terminals, even back office personnel with relatively modest salaries. They need it for their work as well.
Also, keep the hardware connection in mind; even though it's no longer as dominant as before.
yes I think that per seat BBG is probably the most expensive off the shelf software