@Makattak
I understand where your coming from, and I completely agree it is one realistic possible path.
But I also see other possible paths. There are paths to muddle through and yield malaise:
SS & Medicare can muddle through by combination of retirement age changes, broad tax increases, removing the contribution cap while adding means testing, cost of living freezes, rationing medical care, inflation, and debt purchased by the Fed Reserve. The Fed Res could purchase Fed Gov debt and then forgive it. Its not like they have much constraint on action to save whatever the gov't wants to save.
Cutting military spending does not mean complete withdrawal from the world. The Navy + Marines is only about 30% of the defense spending. So without cutting the Navy directly (except for joint service projects), we could theoretically cut defense spending in half.
[this would require withdrawing from all wars, and drastically cutting airforce and army. But up until the 80yrs of WW2+coldwar+korea+vietnam+iraq1+afghanistan+GWOT+iraq2 the US had maintained exactly that posture]
Plus an ascendant China is also interested in protecting world trade and projecting military power, just as much as we are. (How else will they continue to be ascendant in world political influence without doing both?)
So, I agree with you in part, but also see more likely scenarios.
-The malaise can last hundreds of years, until new thinking takes over again and we have a North American Renaissance.
-Or it can grind the nation down for decades until collapse or revolution or both.
-Or it could happen in a few short years.
-Or leftwing immigration [immigrating because of job, but bringing ideas of big gov't with them from home] could be reducing drastically on its own due to the huge wealth improvements of India, China, Canada, Mexico, Russia, Brasil, Chile, and many parts of Africa. Conservatives could out breed liberals. The culture of liberals could be crashing in on itself. Things can still turn around.
I have a hard time assigning the right probabilities to all these scenarios. Each of these scenarios have vastly different preparation paths. I just don't see any one of the paths as set in stone. I reserve the right to change my mind.