YOUTUBE C5IH0ABmyc0 Kent Beck takes a step back and look at TDD in context, including its history, current practice, and potential future.
There is a school of mocking where mocks introduce structural sensitivity. Mocks were introduced as a management technique.
Test Desiderata. 38:54 
Think about what the design would have to be for there not to need mocks for some of those tests even if those tests were smaller or finer grained.
TDD list of effects on software development. 38:25