Competitive rivalry

How aggressively existing competitors fight, which is worst where the product is undifferentiated, fixed costs are high, and capacity cannot easily leave.

Those three conditions together produce the classic value-destroying industry. High fixed costs make it rational to cut price to fill capacity, an undifferentiated product means price is the only weapon, and exit barriers mean the excess capacity never leaves.

Cement, steel and airlines have all demonstrated the pattern for decades.

Look at what happens in the industry's worst year. That is when rivalry reveals itself.