Sometimes, but not always.
Chanda isn't a threat, that's for sure, FOR THE MOMENT ! Let's wait another year .... we'll see.
About the sisters being always together, playing together, having no friends .... well, it's because they were together that they've been able to go so far, because they were helping out each other and standing for each other. They just didn't need the others who anyway, didn't really welcome them. Chanda had certainly more to put up with on her own, but she won't speak much about it, although sometimes she let something go in interviews. Yes, there is racism on tour. No, I haven't been welcome. And so on. But she had to adapt, wheteher, the sisters didn't have to. Sorry if anyone is jealous, but I guess that's the key of their success.
No all of these reasons are certainly true, if you wanna analyse the thing.
Don't argue with idiots, they bring you down to their level and beat you with experience