Roddenberry whored ST as much or more as anybody else
More, IMO, because he was openly and unashamedly dishonest in doing so. The TOS theme song is the quintessential example: He claimed to have lost the contract and needed to sign it again, telling the artist it was just the same contract again but inserting a clause that allowed Roddenberry to give half of all royalties to anyone he contracted to write lyrics for the song. Which he immediately contracted himself to do.
He did the same thing with many, many episodes, changing names of characters or species to claim full ownership of the character and 50% writing credit (which he often left uncredited as a courtesy... but he never failed to ensure that the royalties were properly split).