They don't have an impetus for going all-out like they used to have. Back then, it was the scary thought of a 'Red Moon' and the possibility (however far-fetched) of eventual world control by the Soviets.
IF the NASA scientists of today had that driving force (or deep-seated fear) behind them, they could pull off amazing things. BUT...the country would have to be behind them, and the people coming into the industry would need to be smart, capable of thinking outside the box...and American.
In fact post Cold War NASA has a lot to be proud about.
Their NSTAR engine is a gem although based on a Russian technology.
They managed to refine it and accelerated a spacecraft all across a solar system to near 30000 miles per hour and spent less than a thousand pounds of fuel while at it.
I understand what you’re saying and agree about the lack if impetus.
But it’s more than that. NASA has devolved as an agency. Political Correctness and the inability to even choose “the best and the brightest” have had their impact. Challenger was forgivable. The Columbia was not. NASA’s best is in its past.
I have enjoyed some amazing documentaries I found on YouTube about the Apollo and other space programs, for what it’s worth. The shear magnitude of systems development, testing, manufacturing and management that went into it is mind-blowing. And that’s not even looking at the technical challenges.