Why did they come up with a three-part government in their design?

The Founding Fathers, the framers of the Constitution, wanted to form a government that did not allow one person to have too much authority or control. ... With this in mind the framers wrote the Constitution to provide for a separation of powers, or three separate branches of government.

Explanation:

the three roles stated in the dialogue develop the siblings' personalities.

lloyd's personality looks like a trademarketer

dana's personality is afraid from lloyd's behavior and the oldest sister is a decided person who tries to solve any conflict

health care plans in the united states having high costs because they are focusing on providing quality programs for different groups of individuals. the quality of the service is based on money flow received from the members. without this investment, couldn't be possible a constant scientific searching to prevent death and illness caused because of low levels of health investigation. currently, the complaints are not about the highest cost, but about the coverage and benefits to access the necessary health services required by the members.  

besides, if a global health system is established the quality levels will fall down because of the standardized of the health. the access to care will increase but the quality will be low because it depends on the money invested.