Airlines are a great example of the race to zero profit. Airline margins are slim and thus the cost of travel often reflects exactly the cost of doing the flight itself. JFK to Heathrow requires participation in multiple markets, currency instability, multiple regulators etc which make the cost more excessive. Also london and new York airports are busier than sfo increasing airport fees. Thus in a market with low basically zero margins, the cost from ny to London is more as competitors that cant make the unit economics work leave the market entirely. New competitora cant enter the market at a lower price point because their profit would be zero.