A ten year time period is what the CBO is charged with looking at. If something doesn't take effect until the middle of that period, they have to analyze the last five years and say that this is what the effect is over the entire ten years. This isn't the only item where a lot of stuff hits the fan after the next presidential election.

A massively centralized authority is a crappy way to deal with 300 million people's needs. It doesn't work for anything else, why should it work for medical care? This applies even to things normally thought of as government-provided. Imagine if your local water lines, sewage pipes, road repairs and pothole-filling were directly controlled by someone in Washington DC.