Successful companies with incompetent employees

It's not hard to imagine how a company filled with great people can thrive. More intriguing are the companies that inspire Dilbert cartoons and yet manage to succeed. When a company thrives despite bad service and incompetent employees, they're doing something right that isn't obvious. Not everyone can be incompetent. Someone somewhere in the company must be very competent to keep it alive despite liabilities. Or at least there used to be someone very competent who set things in motion.

Maybe the company is good at attracting investors. Maybe they have enormous economies of scale that overcome their diseconomies of scale. Maybe they've lobbied politicians to protect the company from competition. (That's a form of success, though not an honorable one.) Maybe they serve a market well, but you don't see it because you're not part of that market.