This is pretty much a weakness in all games, and not only games. I have seen it in comics, anime. and tv. How many outfits did Xena wear Charlie Brown had one shirt for decades.
There's a big difference between what you used as an example and what I was trying to say. Those characters you mentioned are meant to wear same clothes because their clothes are basically their costumes and part of their identities. On the other hand, characters in BB are not exactly identifiable by their clothes. Just like in other movies/TV shows that don't rely on costume as identifying feature (e.g.: the characters in Seinfeld, Friends, Fast and Furious, Ocean's Eleven, etc would easily change their clothes in different scenes because you don't associate them with certain look).
If we're talking about adult games, there are games like Dating My Daughter, or Dreaming Of Dana that feature quite a lot of clothing changes to make different scenes feel better. So when it comes to BB, I don't expect the characters to wear something different everyday, but a few rotation of different clothes would've been nice to have, and exclusive clothes for certain events would've been great too. For example, the family members could have 2-3 default clothing that are worn randomly each day, and maybe an event (let's say Alice's birthday) where everyone wears new clothes, etc.
It's definitely something doable for a game like BB that would've enhance the playing experience.