His strength of character. Just like Batman in the DCU, Steve Rogers is respected by everyone, despite: Not being the strongest… Not being a god… Having a fundamental disagreement… Or being with the king of one of the most advanced and rich nations on the planet… He’s the first to protect others from any danger. He’s willing to sacrifice anything for his best friend. Characters that are way more powerful than him, heave a sigh of relief when he arrives to fight . He’s always first in line, no matter who’s in front of him, no matter who’s behind him. Aaaaaaand… Beasts take orders from him; gods fight alongside him; geniuses admire him; kings respect him; enemies fear him. That’s why he stands out. I think this image perfectly sums up who he is. “I can do this all day”. Yup. He can and he will.
Undoubtedly, it was a glimpse into the future. Age of Ultron opens with Tony Stark seeing a picture of the World being overtaken by Chitauri and a mass of fallen Avengers. Tony wasn't the only one who had visions, the premonition of what was to come was also experienced by other 4 OG avengers, these visions clearly connected with what happed in Infinity War and Endgame. For Tony it was nightmare, he was shown that what could happen if he did not volunteer. The very first glimpse we get is of Hulk, who no one thought could be defeated, despite the fact that he was completely decimated. However, he was visibly breathing, indicating that he wasn't dead. This hinted at what would happen in Infinity War, specifically, Hulk losing the fight to Thanos. Thor is lying down with his eyes closed, implying that he is unconscious rather than dead. You could also argue that Mjolnir is just out of reach for Thor, which could be a hint as to how he lost Mjolnir in Thor: Ragnarok, although that...