Why Can't the People Decide?

I was reading about Bernie Sanders' proposal for Medicare for all and the discussion veered into republican obstructionism.  Which got me to thinking.  Why can't the people decide whether we have Medicare for all?  Why do we need these middlemen/women who less than ten percent of the entire country approves of?

We do it at the state level.  We have referendums and initiatives to vote on legalizing marijuana and gay marriage, whether to raise taxes and build a new school, and a myriad assortment of other issues. 

But our national system, our system of "democracy" via oligarchy, does not permit us to do that. 

And very, very, very few question that. 

I've brought this up before on left leaning blogs and invariably was drowned out by general reasons why that won't work and how it's better to just keep allowing these 535 mostly oligarchy controlled politicians to make these decisions for us.

They conclude those decisions are too complex and too important for the people to decide.  The people are too ignorant to make such decisions.  If we do that, a minority of the people will be deciding for the whole of the people.  We can't trust the people.

But we do it at the state level. 

And look how allowing those 535 mostly oligarchy controlled politicians to make our decisions is working out for us. 

It's time for something different.  I'm ready to trust the people, maybe we'll surprise ourselves.