Some of it is fed in directly by the providers. For example Barclays and JPMorgan interest rate swap rates.
There is a network effect: all the customers the dealers want to reach are on Bloomberg, so they have to publish on Bloomberg. If someone else comes along and says "publish on my channel too", that's extra work, so probably won't get done.
There is a network effect: all the customers the dealers want to reach are on Bloomberg, so they have to publish on Bloomberg. If someone else comes along and says "publish on my channel too", that's extra work, so probably won't get done.