Germany, Switzerland, Sweden, Norway, Denmark, and Finland are the pretty obvious examples of democratic socialist countries that are doing just fine. Any implication that socialist platforms are unsustainable is going to have to account for them somehow.

On the other side you have Hong Kong, Singapore, South Korea and Taiwan proving that it's possible as long as there's enough room for growth.

Meh, both our taxes and government spending as a percentage of GDP are lower than virtually any other industrialized country and not by small margins either. We had a pretty good budgetary run in 1993-2000 and there's no reason we can't do it again, we just have to actually give a shit about fixing things instead of shouting about them.

I think you misunderstood my point. Of the ~60 nations with higher tax receipts there are something like 15 that I'd consider successful examples of social democracy. Maybe more, I'm not very familiar with the ex-USSR states.

Of the 117 with lower tax receipts there are four that I'd consider successful examples of laissez-faire.

Why would you assume revenues would fall instead of simply growing more slowly? If expenditures grow at a given percent a year revenues need simply grow at a slower pace to increase the real deficit.