You mean it's not how oligarchs want it to work. Proponents of unpopular policy proposals want to govern people, but they don't want to have to explain themselves to the people they propose to govern.
>You don't make preliminary talks public.
Just because it doesn't always happen, does not mean that it never happens, shouldn't happen, or can't happen.
>Making the above process public will tie the negotiators hands.
Which is the point of democratic processes. It is exactly what people want. I'm not sure what they're worried about anyway, in the US the proletariat has been convinced to go along with all manner of political and economic policy that goes against their best interests; they beg for more of it.