Is it? There were a few DDoS protection services on the market, but they seemingly all dropped KF, so what then? Is that not analogous to kicked out by every ISP?

>I can't grow my own wheat, build my own car [...] - these all require economies of scale. But they aren't natural monopolies, there's plenty of competition in each space. On the other hand, internet is a natural monopoly because the capital costs are so high and are relatively inelastic with the number of users served.

You probably can grow your own wheat or build your own car. But I like your definition of monopoly.

I would say that more generally, that a monopoly is any business that has insufficient competition to motivate them from abusing their stakeholders (including customers, workers, etc.).