Not wrong, just confusing two different movements. My understanding is:

I don't think it's clear where Brutalism first came from, or why Le Corbusier coined it. His style was something different again - detailed, sometimes whimsical, but in concrete.

http://www.open.edu/openlearn/history-the-arts/history/herit... Has a fair summary.

Whether it started as "The New Brutalism" from the Reynar Banham essay or not, it was soon just "Brutalism". That was the architectural style: angles, textures, shadow, imposing mass. A plainer variation without texture or detail. Just ugly slab sided concrete. Both variations co-existed, not just cost-cutting, so probably architect preference too.

It didn't brutalise the users, or shove your face quite in it... yet.

"New Brutalism" was the urban planning movement that Alison and Peter Smithson created after falling out with CIAM. They might have named it more helpfully! "Streets in the Sky" etc. To them it was an impersonal socialist utopia. People were irrelevant. Much of the bad rep of Brutalism is here. The Smithsons seem to have been as good at architecture as they were urban planning (terrible). It's said they led the simpler, plainer variation, but their own buildings had many inconsistent variations from either Brutalist style, they made frequent use of brick. The odd fancy style at variance to everything. Heating and leaking issues were common from new.

Wikipedia conflates Brutalism and New Brutalism too.

We might remember the style less harshly, but it also coincided with significant economy - especially in Europe with post-war rebuilding, and the horrible fad of New Brutalism planning.

The reality was often living in an inconvenient slum in the sky, with poor access, little thought, and nowhere to sit, or let the kids out. They failed quickly as communities and places to live. They often needed repair before first use.

The better examples (most of those we kept) are mostly public buildings, had enough design to be interesting, but worked as buildings. The urban planning of New Brutalism is usually markedly absent. The worst, mostly now blown up, were some combination of the urban planning and cost cutting combined. Usually combined with the simpler slab sided brutalism. No consideration of humans, or life. Often built so cheaply as to need repair immediately. Brutalism of style, urban planning or brutality of life rapidly became indistinguishable.

We arrived at Brutalism the insult. The end of New Brutalism in the UK came with the building of Hulme Crescent https://en.wikipedia.org/wiki/Hulme_Crescents (It's an entertaining read - how to get everything wrong.)

Opened in 72, failing in 73, and the final nail of New Brutalism socialist utopias in the sky. Just three years after opening, 96.3% of residents wanted to leave. Later the estate had the highest suicide rate in the UK.

The architects had also given Manchester the universally reviled Arndale Centre, so far over budget it almost bankrupted the city. Numerous refurbishments were done to try and make it work. It improved, but never really worked before the IRA demolished it. No one killed, but hundreds injured.

The rebuild was dramatically better, though took some years to complete. How the architects got a second job in the city has never been explained.

There would still be the odd building with Brutalist achitecture, the urban planning movement was done.

The early Brutalism of texture, shadow, angles is vastly more interesting than modern curtain walled retail and commercial, with a cliche barn clock, or cutesy feature, and cost as first, last, everything.

Source: I'm old enough to remember them still building this shoddy junk, and making promises about brutalist buildings, Hulme Crescents, shopping centres etc. Fortunately never had to live in one.