yeah what you're saying is right but i think they're going to focus the story on mc, so they don't want to show her sister struggling to get a legendary class aswell but they want her to get one so they made this plot.
but you can say it's a complete coincidence that she got here at the time of destruction and saved that npc which was meant to give the unique class quest to only lvl 1 users, usually lvl1 users keep their item because they don't want to spend money and use these items to level up so none of them are gonna to give up on those item because of NPC and she had helping attitude so she got this class directly usually they must have chained quest to prove their worth
but this is still too much coincidence, like there are total 2 billion players and there was none of them who helped that NPC kid?
