> Monopolies can only be created by government dictate, like old AT&T or modern cable companies.

By virtually every definition I can find, a monopoly is a an entity that functions as the sole, or effectively the primary, provider of a good or service in some market. That seems to perfectly describe Google’s position wrt web-based advertising. Do other ad-platforms exist? Absolutely. Do they exhibit the kind of market dominance or control that Google does? Nowhere close.

> Google has no power to stop them.

Fact? I’d argue that Google’s sheer size and dominance means they don’t need to stop them. Potential competitors simply don’t stand a chance given Google’s size, number of resources, and reach. Explain how that’s not a significant factor into Google “power to stop” a potential rival?

Monopoly does not mean what you apparently think it means. It doesn't matter that competition ostensibly exists. What matters is that anticompetitive behavior is stifling that competition.

It's not a binary. By distilling the entire concept to a dualist perspective, you have evaporated most of the concept itself.

Sorry but you’re starting with a very poor definition of monopoly. If you define things incorrectly, you can make any point logical but the definition (and point) are still wrong.