The argument basically boils down to "America has survived turmoil by adapting before - so we should assume it will again".
But that has nothing at all to do with "America is on the right track". If anything, I'd argue that the current pessimism is fairly warranted, and a crucial step in the process of adapting.
The current format doesn't work for most people, in the same way that it didn't in the 1890s. The way we adapted was by tanking the financial industry (great depression) taxing the ever loving fuck out of the "robber baron" class (90%+ taxes) and creating an entirely new social contract (the "new deal").
We also lucked out with our industry remaining intact while the rest of the world dealt with the fallout of the world wars...
Basically - If anything, we are decidedly NOT on the right track right now, but we arguably have the ability (and may be moderately well prepared) to change course.
Optimism about the status quo is... not exactly warranted in my opinion - although pointing out our strengths is a good reminder that we have the ability to change. But it still requires... you know... actually changing.