It’s true that they have to make more in profit than expenses, but margins aren’t set in stone, except in this country where everyone thinks that not only does already work that way, but that it should.
In a reasonably regulated industry additional costs may have to be absorbed out of the business’s margin instead of immediately being passed onto the customers.
The margins are fucking fat in this country, but that won’t stop them from passing every single additional cost onto you again instead of adjusting their margin.
EDIT: And all of this leaves out the discussion of not only every cost being passed directly onto you, but the responsibilities as well.