I have no idea why anyone in their right mind would underestimate USA even after they have proved again and again why they are the most dominant superpower in the world in the long-term.
Could you show us some of those "proofs" too maybe we can also believe it. Over the past couple of decades the only thing US has been experiencing was a downtrend of their economy, society and military strength. US hasn't had any military victory ever since WWII. They have attacked a lot of defenseless countries though.
For example they sanctioned and disarmed Iraq for 10 years while bombing their defenses and airfields. Then after a decade they invaded the defenseless country and lost the final war.
They also invaded the defenseless country called Afghanistan that was controlled by cavemen (and I'm being literal) spent trillions of dollars and were defeated and had to donate $100 billion to the same cavemen to buy their safe passage while they escaped Afghanistan in the worse way possible.
Every day their bases in Middle East are being attacked and they can't do anything about it. 3 days ago for example one of the biggest bases in Syria was bombed hard.
$7 trillion dollar and tens of thousands of dead US troops later they are fleeing the conflict they started.
I don't know who in their right minds considers this a super power.