You might be interested in reading on many of the other democracies out there that update their constitutions frequently.
And FWIW, there are (by most measures) no other democracies out there which have gone as long under peaceful rule of law as the US. Every other democracy (save by some measures the UK) has fallen to coup or revolution in less than this duration.
Their latest constitutions may work to keep them stable as long as the US has managed. Or they may not. Time will tell.
Are you taking the end of the US civil war as the starting point? If so, then Switzerland has a longer duration of peaceful rule of law.
Even if you do count from the end of the civil war, I would not consider my central thesis destroyed by the small and frankly uniquely weird country of Switzerland. Switzerland is a country that has done very well for its people, but the lessons which have kept it stable and safe over the past two centuries (have a lot of mountains, and don't be worth invading) are not ones which extrapolate out.
And let's be honest -- Switzerland was not functionally independent in WWII. It wasn't necessary to invade, because they did whatever the Third Reich wanted with their stolen gold and borders. This is not the stability I am looking for.
Would you say that Jean-Jacques Rousseau’s political thought has been valuable and influential in the world?
What exactly is your central thesis? It sounds like you're presenting an argument of American exceptionalism, but perhaps I'm misunderstanding your point here.
The real outlier in the US is gun rights.