Strategic choices don't exist in isolation however.
Craigslist owes it's success to a deliberate focus on pleasing it's audience (well that and luck of course). If the prevailing attitude had been on of extracting all available value, it's likely craigslist would't have survived to see it's current success. They would have wasted away at some local maximum.
While in theory it's true that you should always make moves that are +ev, in reality we cannot approach the complexity of operating a business that way. Change has a huge cost in organizations, and the larger and more varied the lines of business you're dealing in, the more expensive that change is.
Put a different way: organizations aren't markets. Organizations can't be ignorant of economic principles, but economic principles alone, particularly microeconomic ones, do not completely prescribe strategy.
That said, it should be no surprise that Craigslist is at the top - they might be leaving more value on the table than any other company in the world.