I tend to think of government like Churchill thinks of democracy when he said: "democracy is the worst form of government except all those other forms that have been tried from time to time."We think that firms are more accountable because they need to be constantly satisfying their customers or else they go out of business. People vote with their dollars every day by choosing to purchase some things and not others, to patronize some establishments and avoid the alternatives.
There are many arguments that can be made for government, but I don't think accountability to the people is among the better ones. Binary yes-no voting every few years is one of the worst information transfer mechanisms I can think of, especially for the sophisticated issues governments face.
Government is the worst form of dealing with issues except that in many instances, it really is the only one that can. I don't think that all of society can be reduced to mutually beneficial market transactions among individuals. I also think that the buck has to stop somewhere. When a problem arises there must be an arbiter and enforcer. A democratically elected goverment that is accountable to the people (and not the highest bidding corporation or special interest) is the only entity capable of meting out justice at times.