What valuable company is nobody building? This question is harder than it looks, because your company could create a lot of value without becoming very valuable itself. Creating value isn't enough—you also need to capture some of the value you create.
This means that even very big businesses can be bad businesses. For example, U.S. airline companies serve millions of passengers and create hundreds of billions of dollars of value each year. But in 2012, when the average airfare each way was $178, the airlines made only 37 cents per passenger trip. Compare them to Google, which creates less value but captures far more. Google brought in $50 billion in 2012 (versus $160 billion for the airlines), but it kept 21% of those revenues as profits—more than 100 times the airline industry's profit margin that year. Google makes so much money that it is now worth three times more than every U.S. airline combined.