That's what they do. But after a while it is not unreasonable to ask people to go and get a job, any job, rather than be paid by the state.
But if you are forcing them into a ZHC the state is paying more as much if not more in work top ups. The employer will then in turn try and keep the employee on as less hours as possible so that they don't have to pay employers NIC. So effectively you have 3-4 doing 1 persons job paying virtually zero employers NIC no sick pay, holiday or maternity pay. Its a win win situation for the employer because the state is picking all that up. It's mind numbing stupid and short sighted brings in less tax costs more in work benefits but gives you that boast look we have the lowest unemployment ever.