It would just be too embarrassing for them. A clear admission of having ****ed up. Not to mention how blatant a slap in the face it would be to everyone who worked on those films. They will want plausible deniability on the matter - ''no, we aren't admitting some failure and repudiating the work of the people we hired, we're expanding the lore in a new direction''
So it seems more likely to me that TFA, TLJ and TROS will remain as the Episodic movie sequels - anyone who likes them will be free to retain them - however, by implementing this world between world's thing they get to play in a brand new pen. They'll still make their money and all they have to do is not put Episode 7, 8 and 9 in the titles of any future project.
