Unfortunately, you’re just unlucky.
With the release of the Year of the Rooster event, many players were eager to obtain the new legendary skins that accompanied the update. Unfortunately, for many Overwatch players, the New Year did not bring good fortune when it came to loot boxes. Many have gone to Battle.net to express their disappointment with how unforgiving drop rates seemed to be during the event, which has led some to surmise that Blizzard intentionally lowered the drop rate for legendary skins.
Once Blizzard caught wind of this they were quick to dismiss the assertion. Director of Overwatch Jeffery Kaplan stated that loot box drop rates for Year of the Rooster were the same as they had been for the Summer Games, Halloween Terror, and Winter Wonderland events.
If loot box drop rates have not been altered why do an increasing number of players feel they had a harder time obtaining legendary skins then they had in previous events? Well, the simplest possible answer may be luck. Since loot boxes are a game of random chance, it is statistically possible that a larger percentage of players were not as fortunate in getting legendary skins as they had been in previous events. Unless evidence surfaces that disputes Kaplan’s statement, players will just have to hope their luck improves.