A charger made the right way would consist of a constant current generator fixed to an high voltage value, say 24V, leaving the circuit into the appliance to step down it and draw the required current until voltage drop is acceptable. This way one could have 100% short circuit protection and multiple appliances charging in parallel. A phone charger could even be used to recharge a laptop, it just would take more time to do so but it could be done.

The next question is who is going to pay for a charger that can charge an electric car but is only used to charge a phone. It is more expensive (and bulky) to provide more power safely.