One easy answer is to give people an "appliance"/task-specific computer instead of a general purpose computer. So the computer is essentially just a hypervisor

One easy answer is to give people an "appliance"/task-specific computer instead of a general purpose computer. So the computer is essentially just a hypervisor that loads the appropriate appliance which only allows them to do specific tasks - one for banking, one for email, one for writing documents, one for browsing, one for gaming, etc.