By your own logic, those in charge should've created their own sci-fi universe instead of bringing back what was dead and finished for The Motion Picture
No that reflects your tenuous grasp on logic that you think that's actually comparable. TMP was a TOS based movie following on from the TV show and with the original actors playing the characters they made famous.
As I've said, Star Trek *is* the universe that TOS created, "Roddenberry's vision" or whatever you want to call it. Continuing to tell stories within the universe he created in TOS is not a cynical use of the Star Trek name. Bringing back the characters he created from the dead and trotting them out in some flashy "reimagining/reboot" set in an alternate version of his trek universe is.