Optimism is a trademark feature of a population untouched by traumas of war or famine (how many wars were fought on American soil? Would you say American military veterans are an optimistic bunch?).
Otherwise it's an individually variable characteristic.
There is no boot crushing this face or jaw. Everyone is working together to win together across the entire United States. It is cheap online astro turfing and gas lighting and psy ops bullshit that would suggest otherwise. The data shows that the long-term view of the American narrative is intact and stronger than ever.
It is individually variable because we are talking about hundreds of millions of individuals. But it is universally applicable, across the United States, because it's built into the basic charter of the country (the Constitution) and has also been taught to the children for decades still. We may be experiencing a slight negative blip in the road by confronting a lot of negativity and toxicity and psy ops online for now, but the reliable data and the verifiable real-world experience across the United States on this front resolutely demonstrate that American Optimism is truly a value that continues to exist and fuel the next batch of massive innovation in products and services boosting everyone including the lowest classes.