Why might governments nationalize firms, and why might a government-owned firm have an unfair advantage over privately owned companies?

Low production, tax relief, subsidies

Explanation:

Government-owned firms have substantial advantages compared to privately-owned companies, which is why it takes significant efforts to stay and compare in the market. Government-owned companies usually get tax reliefs and subsidies which leads to economies of scale and low production cost. Similarly, government give funds to support those firms, which is the main reason they have an unfair advantage over privately-owned companies.