Here's the way t.v. animation development happens*:
1) Scripts for a cartoon series are written and handed off to in-house board artists.
2) Boards come back. New animation exec says: "These things are too costly. ... I know! Let's freelance them out!"
3) Boards are freelanced out. Come back. General reaction is "These things look like shit!" (Of course they do. The freelancers are doing the boards quick and dirty so they can make enough money to maintain their "going rates.")
4) An exec says: "Let's hire some in-house board revisionists to clean up these shitty boards." So revisionists are brought on staff to improve the shitty boards.
5) Another exec suggests bringing board artists in the studio "to improve quality." Management agrees this is a fine idea and so hires in-house board artists.
6) The consensus soon is: "Heey. The production boards are improved!" A little time goes by and a new executive says: ""These things cost too much!" ...
Rinse and repeat.
* With the spread of the ubiquitous Cintiq, this pattern is changing. Now in-house production board artists are starting to build and time their own digital animatic story reels (along with partially animating them.)