Governments have lots of other incentives (like job creation, elections, income distribution)
A lot of private companies effectively operate above the law too! In theory the law can be enforced on them. In practice it often isn't.
A government has a monopoly on violence. A government has a monopoly on money printing and taxation. A government has a monopoly on the legislation. A government has far more human and financial resources than any other economic actor within its borders.
If a company goes out of business, people lose their jobs. If a government goes out of business, people lose their lives.
It is not a difference in degree, it is a difference in kind. There is a reason that economist distinguish between private firms and government.