The natural tendency of government is to build upon it's power base, yes, but it is by no means inevitable.
For instance, the government used to be able to formally discriminate based on race. That isn't the case anymore.
It used to be able to jail you for sedition during war time. That is no more.
It has grabbed power in other places, and will continue to do so if possible, but I think that is mostly due to electoral laziness and a widespread sense of apathy. When large groups start giving a shit about securing their privacy and individual freedoms, the trends will be reversed.