1. Barriers to Entry: Monopolies are characterized by high barriers to entry, which prevent new firms from entering the market. These barriers can be natural, such as economies of scale, or artificial, such as patents or government regulations. The higher the barriers to entry, the more likely the monopoly is to maintain its market power in the long run.

2. Demand Elasticity: The elasticity of demand for the monopoly's product is also an important factor in determining long-run equilibrium. If the demand for the product is highly elastic, meaning that consumers are very sensitive to changes in price, the monopoly will have less pricing power and may have to lower its prices to maintain its market share. If the demand is inelastic, meaning that consumers are less sensitive to price changes, the monopoly will have more pricing power and may be able to maintain higher prices in the long run.

3. Production Costs: The cost of producing the monopoly's product is another important factor in long-run equilibrium. If the monopoly has high production costs, it may not be able to sustain its market power in the long run, as it will have to charge higher prices to cover its costs. If the monopoly has low production costs, it will be able to maintain its market power in the long run, as it can charge lower prices and still make a profit.

4. Technological Change: Technological change can also affect long-run equilibrium in monopoly markets. If new technologies emerge that make it easier for new firms to enter the market, the monopoly may lose its market power over time. On the other hand, if the monopoly is able to innovate and develop new technologies that give it a competitive advantage, it may be able to maintain its market power in the long run.

5. Government Regulation: Government regulation can also affect long-run equilibrium in monopoly markets. If the government imposes price controls or other regulations that limit the monopoly's pricing power, it may be more difficult for the monopoly to maintain its market power in the long run. Conversely, if the government grants the monopoly special privileges or protections, it may be able to maintain its market power in the long run.