For the next 100+ years, every American gen will be worse than its precedessor. There's a strange American exceptionalism that believes that the US is uniquely positioned to be great forever. Likewise, there's this immaturity that takes it for granted that every generation ought to live better than its parents' generation. The sentiment, "my parents could afford to buy a house after working just for a few years and it's impossible now."
I would argue that America's superpower status is a temporary condition of history. The US gained access to an extraordinary rich geographic land mass from the native tribes unlike Europe and Asia. And it was 2nd order country until really the late 1800s/early 1900s. The devastation caused by WWII allowed the US to become the sole superpower.
But there's absolutely no inherent reason why it would stay that way.
When we say we're the best and a superpower too, we're mostly talking about economic indicators to measure progress. Versus say education, health care, gun violence, mental health (anxiety, depression, medication use), obesity, physical health, suicide rates, and so on which have been getting worse over time.
A lot of the wealth generated in the past 50-80 years could have been reinvested into the commons but instead was kept by the wealthiest families and institutions. And I don't see any reason why they would willingly cede that power or invest it back into society.
Having said all this, it's likely true that the US will continue to still have a high standard of living RELATIVE to other countries.
But unless some radical social/economic changes are made like UBI, I'd expect the average American family will continually have a worse livelihood, health, education, etc. than their parents for the foreseeable future. But, there will still be the wealthy class that will get to reap the majority of benefits.