The only reason The Barbican (London) works is because wealthy people moved in. In my opinion, it's still a very ugly estate but it is a well maintained estate. So people can still admire its design.

Whereas other examples were left to deteriorate because wealthy people moved elsewhere. And thus all people see is dilapidated, ugly concrete.

While we are on the topic of brutalism, one of my most disliked Sci-Fi tropes is concrete buildings used as "futuristic" buildings. I honestly think the only reason they do this is because concrete is featureless so it could be from any era. If they used Victorian-style architecture or Germanic Gothic buildings then all you'd see is historic-looking architecture which would pull you out of the moment. But I, personally, cannot "unsee" concrete buildings in Sci-Fi. Everytime I see that I just see lazy set design. Plus I'd hope in a few hundred years we'd have found a better building material than concrete.