It's an expenses which isn't needed for any business. Why should a business have too many staffs than they require? Business is not a charity case because businesses are run on cost. If a staff isn't making more money for why he or she was hired, their services shouldn't be required.
Seriously, this is practically the reason why I don't stay lenient with any of my employee that's not performing. There's no way you would expect me to pay your salary when you didn't do much to boost my business profit for the week or month. When you have low productivity, you're getting low pay.