That's a HUGE reach considering WW2 survivors are still alive not to mention the Korean & Vietnam wars. The implantation of the UN, the establishment of Israel, the Martin Luther King era and how he's effected life today with the end of segregation. (150 years to late IMO but his courage remains unmatched) What about 911 and millions of lives lost since?
Biggest story of our lifetime so far? I most certainly think not.. it's not even the biggest story currently. Ask those in Syria or Iraq or Yemen or Iran or Libya if covid is the biggest story? Biggest story of our lifetime, just a really bad sentence as it is minuscule in comparison with the really big stories!
I appreciate your empathy and global perspective, but by "our" lifetime I meant Americans under 93 (my dad, a WWII vet is still alive) and given American's zero fluency in the affairs of Syria, Yemen, Libya or pretty much any other county, I think my claim is much less of a reach. Few stories are global in the same moment. This is one of them.
Of all the dramatic and affecting stories you mention, none of them brought the American economy to a grinding halt, threatened repercussions as serious as the Great Depression, closed our schools, churches, sporting events, and basic human contact, and extended consequences into every home regardless of geography, income level or political affiliation. The nature of a pandemic also delivers a psychological hit you don't get from a conventional human enemy.
We were glued to the TV during 9/11, but free to go anywhere we wanted. Vietnam was a s#!tshow and a nightmare, but as kids we played happily through it and Nebraska won two national championships. 1968 was comparable to 2020, including riots in the street, but you can't deny COVID adds another layer of existential dread. If you want to get more into it, COVID has further fueled an American civil war where patriotism is on public display by your willingness to wear a mask, or not. Frankly, the whole story is likely a drop in the bucket compared to what my kids will face with global climate changes over the next 50 years.
I'm not the first person to make this reach, either. There have been some really good articles about what an American born in 1900 would have lived through, compared to what the post-World War II generation considers deprivation and sacrifice.