League of Legends has been around for over 12 years and now has over 140 different champions, each with its different lore. A lot has been subtly changed or outright abandoned or reworked - when did you last hear a reference to the Fields of Justice, for example?
Considering just how many champions there are and how involved League's lore is nowadays, it is quite the accomplishment that most champions have lore that firmly roots them in the world of Runeterra and gives them a unique, interesting identity. Some, sadly, are not so lucky. Whether their lore no longer fits with the newest version of the setting or is just not that engrossing, they feel left out. Hopefully, the loremasters at Riot will get to them soon!