The govt don't have any money. Actually they do. They even create some of it electronically. As for tax revenue, if anyone doubt's it belongs to the govt, perhaps they should stop paying local/national taxes, assuming they do in the first place of course.

Without the infrastructure provided by taxes, in terms of roads, schools, health etc, individuals and businesses could not operate in the same way, or make the same money. Having custody of money doesn't equate to having legal title