[_IsThisRealLife]

As others have mentioned there is a large amount of expert knowledge to collecting and organizing extremely disparate data sets. There are also longstanding business relationships, lots across a lot of markets, and a reputation for great data security, that has many pricing sources and exchanges offering data almost exclusively through the terminal, and some folks putting their own data into the system. The risk with mishandling(making unavailable or available at unreliable/inconsistent times, for example) some of that data is just so high that 30+ years of reputation in some spaces is worth a (maybe perceived) premium.