In general, the only sector that generates money in the kind of society we have today is the business sector. It's the only profit-making sector. So, yeah, you can't underestimate its role in the economy.
However, it's the government that makes sure this sector thrives. Investors and entrepreneurs can only survive and flourish if the government creates a healthy business environment. So, you can't also underestimate the role of the government.
In every successful society, it's always a healthy mutualism that propels it forward.
Almost every sector of the economy is business oriented and needs good government policies to thrive else they might not be able to survive especially in this part of the world, it is also important to note that the government can't employ all of its citizens which is why the private sector happens to be one of the key areas of the economy through which government generate a significant amount of her revenue and also relies heavily on this private sector for the employment of its citizens also but if the policies of the government isn't friendly enough for investors who run the private sector, how do you expect them to come to your country?