Do we blame the ice maker manufacturer when poisoned water flows from the city water pipes? Do ice machines have viral and chemical threat detection? Wouldn't the ISP be a better place to assign liability? Or, perhaps, just maybe, the actual user of a device? It's not Lenovo's fault when a user gets a virus.
I agree device security ought to be better, but the free market can solve that. If a particular brand of toaster is constantly being hacked, the market would respond. I wouldn't expect an ice maker manufacturer to be held liable for poisoned water supplies.
It's a tough issue, but 'more government' isn't the answer. The government can barely keep their own data safe let alone be trusted to enforce how others ought to keep their's safe.
The FDA is supposed to keep medicines safe yet it has become a monster that adds billions to the costs of drug development. I am not saying to ditch the FDA, but I would be fearful of releasing a new IOT device required FDA-level approval. Your connected toaster would cost $9000.