"They might be if Daz has them sign a contract..."

I have never heard of anyone signing a contract with any of the brokerages in the 8+ years I have been doing content creation. I would guess there are potentially staffing contracts done by brokerages but that isn't the same thing. Exclusivity is expected at Daz for most products (which is not the same as the content creator selling there exclusively) and that may hold true for Hive wire as well. Others strongly encourage exclusive products for obvious reasons. How far a brokerage will go to try to encourage exclusive sales through that brokerage varies, but most simply go on a product by product basis with no really benefits to having all your eggs in a single basket other than those that you get from not splitting potential sales at a variety of places.

www.Calida3d.com
Daz studio and Poser content creators