Monopoly refers to a situation where a single seller is dominant over the market. It is the situation where only one seller serves the whole market.

One can agree with the fact that without government intervention, there will be no long-term monopoies. The real world is dynamic and the free market (where there is no government intervention) leads to an increase in competition. Additionally, technological advancements and innovation help reduce entry barriers. This encourages new firms to enter the market. It will create more competition and each firm will try to earn the maximum share in the market which may undermine the monopoly power. Government intervention in certain instances plays a role in maintaining a monopoly in the market when it approves patents to the monopolist or holds some restrictions for the new firms that try to enter the market. But this would be mostly to promote consumer welfare.