What can make price wars more likely?

The recent drop of the oil price was caused by a price war. What kind of property makes price wars more likely to happen? There are three properties I think. Firstly, if suppliers have different costs of production, there will be a higher probability for a price war to take place that suppliers with lower cost of production start a price war to remove their competitors with higher cost of production from the market. Secondly, the products have to have very close properties. Otherwise, price competitors will not take place. Thirdly, a single supplier in the market need to have productive capacity to supply  a majority of the total market demand; otherwise, suppliers will not start a price competitor if they can increase their production when their market shares increase. From the above three properties, we can see that the industries are generally low-end traditional industries. These industries usually have very low margins as well. The unprofitable industries can hardly attract new entrants. Therefore, after several price competitions, the low-end traditional industries could become highly concentrated or even monopolistic.