Pinker is an extremely intelligent guy - a real heavyweight Harvard intellectual. I've read a deal of his stuff in relation to language as a part of my degree, and it was always insightful if cerebral. I know he was criticised (in relation to the views he expressed in that video) for being TOO academic and dismissive of individual's experience. That is to say, he measures 'better' with statistics and objectivity.
I can see the criticism. It's of little comfort to an individual living in poverty today to know that actually, relatively, they are measurably better off than they might have been 50 years ago. It still feels like suffering because inequality still exists, and is arguably worsening. Whilst the poor of today are better off than the poor of yesterday, the gap between themselves and the wealthy is getting more profound. The rate of progress is unequal.
What Pinker says is undoubtedly true (imho) and the context is key to accepting what he says. Yet there are other contexts, more subjective ones, that are equally true. It makes you (well, me anyway) ponder the complexities of truth.