These announcements are planned well in advance almost down to the hour, and involve marketing asset creation, coordination with the IP holder, etc. So let's say it gets leaked on July 1st in your example, not seemingly a huge deal, except the IP holder had a whole campaign planned in conjunction with something else (maybe a TV show trailer release) all building to a head on Aug 1st. Assets created and social posts scheduled for July 15th as a teaser, marketing campaign with grocery stores set to go into effect July 22nd, press releases being written for July 31st and whatever else to follow. Now not only is that luster lost (and causing a mad scramble on their end to advance their timeline), maybe some contracts haven't even been signed yet and now there's some uncertainty, oh and also maybe IP holder #2 is now upset because their reveal was going to be July 10th and now their spot has been pre-empted.