She lasted because season 2 used her as basically nothing more than a two episode romantic plot device for Jean-Luc, and I expect for season 3 to do the exact same for one episode before dropping her completely for the rest of the season. So, she didn't last because they gave her a lot to do or wanted to give her more backstory and scenes and let her stand on her own (which would have been the way to go since she was clearly and rightfully a fan favorite after season 1) - she lasted because for some reason she was the only one the show could come up with as a love interest for Jean-Luc even though Q was right there and frankly, even if I WASN'T into Picard/Q I would still say the romantic tension between Jean-Luc and Q was about a zillion times more believable and intense than anything he had going on with Laris.