Kevin Werbach nails it as usual with his note What is Internet infrastructure?. The key phrase here is: …a few simple and non-proprietary core connectivity protocols make innovation possible elsewhere…. I would go a step farther and add that the core protocols of the Internet allow an incredibly rich set of innovation, i.e. they are absolutely brilliant in how unconstraining they are.
This is what scares me with some of the efforts to push identity deep into the Internet. While that may be a desirable feature of the core protocols (and services), it feels fundamentally different in its effect on innovation on top of it, especially since many of the motivating forces are efforts to control and limit certain activities from happening.