One example of brutalist architecture being saved in each capital city is probably sufficient in my opinion, if only as a lesson on how not to design a building. Ask the general public who know nothing of architecture but know what they like, hey that's me, I doubt many would want to save brutalist buildings. Show them a Victorian,
Federation or Art Deco building and they will cry out to save it.
I don't particularly like most art deco but I know that others do. I do like post modern and brutalist, which one could say is in it malaise period (especially brutalist) and thus a target for contempt and in turn demolition. Art Deco was probably like that at some point in time but maybe was not such a target during those times as there may have been less redevelopment taking place? There's also the fitness for purpose question, and in these times I believe the brutalist architecture still retains a high level of fitness for purpose and merely require renovation and some minor restyling to become contemporary, or less ugly to those who somehow dislike the style.