That seems pretty reasonable too. I like the idea of making the business liable regardless because it more or less automatically optimizes the combined cost of security and losses. Companies will in theory spend money on security until each dollar spent mitigates less than a dollar in losses, then stop.

The trick, of course, is making sure companies estimate their risk properly and don't just screw everyone over by underspending on security and then going bankrupt when hacked. Mandatory liability insurance could help with that, since insurance companies basically exist to assess risk in something like a realistic fashion.