I think the ideas are very interesting. I don't agree with his condemnation of Docker and single-threaded programming, but he's certainly right about the value of being able to kill threads in Erlang, and about the importance of being able to fix things that are broken, and about our computers cosplaying as PDP-11s (and the consequent teletype fetishism).
I hadn't made the connection between Sussman's propagators and VisiCalc before. I mean I don't think Bricklin and Frankston were exposed to Sussman, were they? They were business students? But if not, it's certainly a hell of a coincidence.
My defense of single-threaded code and aborting is that the simplest way we've found so far to write highly concurrent systems is with transactions. A transaction executes and makes some changes to mutable state based on, ideally, a snapshot of mutable state, and if it has any error in the middle, none of those changes happen. So it executes from beginning to end, starting from a blank (internal) state, and runs through to termination, unless halted by a failure, just like the "dead programs" Rusher is complaining about. You put a lot of these transactions together, executing concurrently, and you have a magnificent live system, and one that's much easier to reason about than RCU stuff or even Erlang stuff. This is what the STM he praises in Clojure is doing, and it's also how OLTP systems have been built for half a century. Its biggest problem is that it has a huge impedance mismatch with the rest of the software world.
I've said before that to get anything done you need some Dijkstra and some Alan Kay. If you don't have any Dijkstra in you, you'll thrash around making changes that empirically seem to work, your progress will be slow, and your code will be too buggy to use for anything crucial. If you don't have any Alan Kay in you, you'll never actually put any code into a computer, and so you won't get anything done either except to prove theorems. Alan Kay always had a fair bit of Dijkstra in him, and Dijkstra had some Kay in him in his early years before he gave up programming.
Ideologically, Rusher is way over on the Kay end of the spectrum, but he may not be aware of the degree to which the inner Dijkstra he developed in his keypunch days allows him to get away with that. The number of programmers who are ridiculously unproductive with Forth (i.e., almost all of us) is some kind of evidence of that.
Interestingly he doesn't talk about observability at all, and I suspect that observability may be a more useful kind of liveness for today's systems than setting breakpoints and inspecting variables, even with Clouseau.
Data Rabbit, Maria.cloud, Hazel, livelits, and Clerk sound really interesting.
I think it's unfortunate that you switched the URL; even for people without hearing impairment, transcripts are far preferable to videos, and this is a really excellent transcript. With a couple of screenshots, it would be better than the video in almost every way, though a few of the demos would lose something. (The demos start at 14'40".) The sort of people who were making worthless comments because they were confronted with a webpage formatted in an unfamiliar way won't suddenly start making insightful comments because there's a video link; they won't make any comments at all. So it's a mistake to cater to them and damage the experience for people who might have something to contribute. Video links make for shallow conversations.