I think this is a combination of two things. Firstly the common business definitions of monopoly are weaker than the common economic definitions of monopoly.

I think this is a combination of two things. Firstly the common business definitions of monopoly are weaker than the common economic definitions of monopoly. In some cases the Michael Porter's of the world are happy to call something a monopoly casually if it has any unique selling point. Secondly, the standards for companies that raise venture capital are higher than for most normal businesses.