The important difference is that if a firm accumulates too many of these organizational pathologies it can be allowed to collapse and be replaced. In theory you could do that with government departments, but I've never heard of that actually happening. Goodness knows the US Department of the Interior could use something like this.

Democratic accountability helps to keep the "parasite load" down, but only so much and only to the extent that problems capture the attention of the public (see again about the Department of the Interior). To the extent that the government does more stuff there's less democratic oversight on any particular thing that it does.