Why do rolls come in 6 and 12packs?

Why shouldn’t they? Would you prefer to buy them in packs of seven?

Maybe because they are traditionally sold/priced by the dozen?

originally sold in thirteens - hence the saying “a baker’s dozen” as weights and measures became more accurate however, they were able to sell them in twelves.

Is there a question about hot dogs that you also wish to ask?

There was some talk a little while back about eggs being packaged in sevens over here. It was supposed to encourage people to eat one a day. I haven’t seen them in the shops though.

Nothing is too banal for Cecil. Why do hot dogs come 10 to a pack while buns are 8 to a pack?

How my mind turned the OP into a drug reference I’ll never know…