Be careful what you wish for.
When the Congress or President feel impelled to "DO SOMETHING" to make electoral points, the results usually stink. This is regardless of which party is in charge. The recent immigration flap is a great example.
Our current health care system is complicated, and maybe more expensive overall, but it works, and there's choices you can make. Even the post office has competition.
If you reduce it to a single system, you get more simplicity, but the same would be true if you only put one brand of everything on the store shelves. Simple and cheaper...but you'd better hope it's the brand you like.