I can only comment from series 5 onwards but I'd say so @ElspethFlashman - I can't think of a queen that has been in this long that didn't deserve to be. Even if they didn't win challenges they still brought it.
the only one I remember thinking was out of her depth was Joselyn Fox in s6 who got to top 6 (I think?) and I thought she was the weakest link but she was genuinely such a sweetheart it didn't matter so much and we all knew she wasn't being pegged to win with Bianca and Courtney leading the way.