She just has the best luck of any actor in terms of awards, and she got cast in great movies. I mean, is there any other actress who had lead roles in 3 movies that either won Best Picture or were the runner-up to the Best Picture winner? She might be the first actress who achieved this in the entire history of the Oscars.
Best Picture winners or runner-ups in the last 30 years that had a leading actress nominated:
1991 - The Silence of the Lambs - Jodie Foster
1993 - The Piano - Holly Hunter
1996 - The English Patient - Kristin Scott Thomas
1996 - Fargo - Frances McDormand
1997 - Titanic - Kate Winslet
1998 - Shakespeare in Love - Gwyneth Paltrow
1999 - American Beauty - Annette Bening
2002 - Chicago - Renée Zellweger
2004 - Million Dollar Baby - Hillary Swank
2013 - Gravity - Sandra Bullock
2016 - La La Land - Emma Stone
2017 - The Shape of Water - Sally Hawkins
2017 - Three Billboards - Frances McDormand
2018 - Roma - Yalitza Aparicio
2020 - Nomadland - Frances McDormand
She was already the only actress who had two movies close to winning Best Picture in the last 30 years, and now she has 3 movies, while the other big names struggle to get cast in one, as the Oscars favors movies with male leads. Actresses like Meryl Streep or Viola Davis would probably have more Oscars if they would pick movies as "efficiently" as McDormand does.