These classic places you speak of survive time because they are attended to furiously. They are things which degrade exponentially without attention and they are ongoing sinks for human capacity in support of their own ostentatiousness. They may please some eyes because they are so out of character. They are rebels against nature and humanity. The inspire us to be other than what we are - godlike and beyond our natural limitations. They are feats of design, but they are more limited in what they express. The idea of working in them makes me feel like I am being conquered by other people's limitations and conformist ideas of beauty.
In disrepair, both will eventually crumble. In brutalism, I see my condition, but also my opportunity. In classicism, I feel distracted from my condition and oppressed by those who would put forth pomp while taking away individuality and opportunity.
Trophies of monarchies vs. triumphs of people.