So why don't the creators just give it a new name, place the stories in a new universe and stop trading on a well established and beloved franchise?
They are profiting by trading on the name and that's the only reason. TV shows that don't get instant audiences don't get or keep advertisers and don't last as long. The history of spinoffs and sound-alike TV series has a long history. Star Trek is one of the biggest franchises to take advantage of it's name. Would Star Trek: TNG have been as popular by any other name? How about Star Trek: The Movie? How about the abundance of Law & Order and CSI spinoffs? How about all the current reboots including Magnum PI? Some of those producers tried similar shows under different names and they were cancelled quickly. Star Trek: Discovery by any other name probably wouldn't get made with the same production or promotion budget and it wouldn't attract the same quality of actors and other personnel.