Since that time HAMT was invented and successfully used in Scala and Clojure, so this talk didn't age well.
Wikipedia (https://en.wikipedia.org/wiki/Hash_array_mapped_trie) links to the paper describing HAMT (https://infoscience.epfl.ch/server/api/core/bitstreams/f66a3...) and claims that is from 2000. That talk is from 2016.
Do you know of any implementation, that is well annotated/commented, so that it is easy to understand?
HAMT weren't immutable/persistent until Clojure though:
https://en.wikipedia.org/wiki/Persistent_data_structure#Pers...
Still well before the talk.
I think he was always reluctant to add features, and his version of Python would be slimmer, beautiful, and maybe 'finished'. His voice is definitely not guiding the contemporary Python development, which is more expansionist in terms of features.
“What has been is what will be, and what has been done is what will be done; there is nothing new under the sun.”