Sure, liability and regulations pay a role and those problems need to addressed. Regardless, the answer is NOT to have government pay for prescription drugs for seniors. That only makes the core problem worse.
That would normally be my take on a market, however after paying close attention in the threads that delved into the workings of the pharmaceutical market on the global scale, it is clear that the US market subsidizes the research and development of all major drugs. If you don't reduce the costs, then massaging who pays them doesn't really solve the problem.