> The only issue is that even "common sense" socialism doesn't work in the long run. All generous welfare systems run on unfunded liabilities. That amounts to a Ponzi scheme, which will collapse along with the birthrate.

I am not sure I understand your point. "common sense" socialism has been more or less in use in Europe for decades. It does evolve from time to time and depending on the political climate and economy, it can face some financial issue, but it has been in used for at least as long as the end of WWII.