Perfectly Framed

For once, for all ye abstraccionados:

If the 18th century marked the rise of liberalism, nowadays right-wing conservatism, the 19th century brought forth modern-day “progressive” socialism. And let’s say the 20th century may be framed as both the clash and their integration, or (Hegelian) synthesis.

Why then would we look upon the 21st as a loss of Idealism, while both these Ideas have been more successful than almost any other? 

I will refrain from pointing out the obvious in Western politics.