Why do we need "open access"?

I got the question yesterday again, why we need open access, or why do we need network neutrality.

I have three reasons why that is needed:

1. Transparency: End users, that buy access, must know before they sign a contract what service they will get. This implies both transparency and the ability for customers to compare the products of two competing providers.
2. Investments: The providers of access must be able to use traffic management to ensure the user experience for the end user (their customer) stays the same over the contracted period. On the other hand, an access provider should not replace investments in more capacity with traffic management.
3. Innovation: Innovators, and specifically public services that provide new services need to know how to design their products so that it can be used by as many customers as possible. We can not accept a future public service that require end users to be customers of a specific access provider.