It is fun to run a monopoly. But in the long run, it can be a lot less enjoyable to own one.

Why?

Companies change as they grow larger and more profitable. Bureaucracy and success slow innovation. Will this new product hurt an old one? If so, should we delay, or price it very high? Old monopolists find themselves outrun by newer companies with no stake in the old ways.

Bosses of monopolies are highly unlikely to view themselves as lucky rather than brilliant. Being better than everyone else, they act haughtily toward competitors and customers alike. People start looking for a way to even the playing field.

Eventually, the antitrust lawyers arrive. With them comes the threat of management sclerosis, because the lawyers’ presence affects corporate behavior. Once a company comes to understand that being too successful may be bad for its future, it is really hard to stay on the cutting edge.

This week, the French Competition Authority officially declared Google a monopoly. That conclusion is hardly novel, but the decision appears to go beyond any previous official ruling in the United States or elsewhere.