Your examples are flawed. In two of the cases, the "assets"(children and dog) are specifically not deemed responsible due to their lack of maturity/lack of understanding of societal norms - so we instead find the "owner"(or more properly named, parent/guardian) at fault - they are supposed to keep the children or pet in line.

In the case of a loaned car, you are not liable for damages that the person you loaned the car to causes(perhaps you're confusing it with insurance liability?). I don't know about the contractor case.

How is your "practical and effective" solution any different from a fine? You fine the company $300 mil, or you seize $300 mil of shares and sell them.