However, one way to establish authorship, and that all-important "Created by" credit, is to write the pilot AND the show bible. Part of me suspects that Roddenberry massively rewrote Farpoint and pushed Gerrold out in order to put his stamp on both pilot and bible to make certain that he didn't have to share the "Created by", and all the money that goes with that, with others.
Although he should've had to share it anyway. Per WGA rules (which I looked up the last time this came up), there are two main ways to get creator credit: To write the series bible or to be the credited writer of the pilot script. Gerrold co-wrote the bible and D.C. Fontana is credited as the co-writer of the pilot, so one or both of them were entitled to creator credit alongside Roddenberry. The fact that they got denied it is highly irregular. I read that the WGA's reason for giving him sole creator credit is that TNG was derived from the original
Star Trek, but that doesn't fit the pattern of other spinoffs like the later Trek shows,
The Bionic Woman, Angel,
Stargate Atlantis, and the like, which all give creator credit to their own developers rather than just the parent shows' creators. Roddenberry was certainly entitled to creator credit for TNG, but he should've shared it with Gerrold and/or Fontana.