I think the renewed popularity of "socialism" with the young, has 2 root causes:
1. The young and idealistic want things to be fair and ethical.
The 24/7 news cycle and peak behind the current on Wall St helped reveal
the deck is stacked in favor the wealthy/well connected.
Of course it always and always will be regardless of the system put in place.
They party leaders of the dear ol' USSR were very corrupt .
2. Gov and systems can be toppled and changed. The USSR collapsed and Castro took over Cuba with his
rag tag bunch.
Bernie Sanders got a movement going and damn near rode it to the dem nomination.
Most generations start out starry eyed and ready to change the world. Most fail .
Basic reality says that the US( mostly) capitalistic systems is the best one for the avg Joe.
It's hardly perfect but beats all those other systems tried before.
Simple probability shows that most of us will end up as avg working slobs ,
live obscure lives, posting on some goofy forum.