Two of the core ideas are that the majority of the work can be undertaken by a single person with basic carpentry skills, using readily-available materials in standard sizes so there is minimal cutting and waste.
Having built a couple of smaller structures, I don't see why these can't be done today. Ignoring the current trend of building for curb appeal instead of practicality, you can build a house using standard size materials (8/10/12/16 foot). Even studs come in 92 5/8" to accomodate for top/bottom plates in 8 foot walls.
I'm always intrigued by the Segal method, but it's so closely tied to the sizes of construction materials available at the time and I can't help wondering if anything has changed since.
I've been thinking about doing this, and my main thought is that the insulation standards were probably effectively non-existent at the time, beyond "as few draughts as possible"!
Edit: not sure if these will be geo-blocked, but there are a couple of programmes about that project here:
Oh, absolutely. It's just that I've seen some of the original buildings in south east London and they looked absolutely freezing - single glazing with metal-framed windows. The walls looked like thin painted plywood, but I don't think that can be the case. It looks like they've updated them now: https://programme.openhouse.org.uk/listings/1615
Two of the core ideas are that the majority of the work can be undertaken by a single person with basic carpentry skills, using readily-available materials in standard sizes so there is minimal cutting and waste.