You must be a sophist. I chose a metric where we can discuss without injecting our own subjective opinion. We can objectively say that both actresses are acclaimed by the public, the critics and their peers. We can objectively quantify these thousands of subjectivities looking at the number of awards and nominations and do so using the same source as a way to fairly compare different actresses. If you want, we can debate our individual subjective opinions on the matter, but we might reach a dead end pretty quickly considering I saw 10 movies and a whole TV show with Brie Larson and I have not seen Captain Marvel. We can beat around the bush, but that's the crux of the matter : people saw Blunt in movies they liked (Sicario, Edge of Tomorrow) in which she delivered serviceable performances and saw Larson in Captain Marvel, in which she apparently delivers a poor performance and in Kong where her part is non-existent. So, suddenly, Larson is a no talent hack and Blunt an amazing actress (amusingly her best acting job that I have seen was in Your Sister's Sister that I doubt that you or
a c i d.f l y
have seen). Same goes with Kristen Stewart and Jennifer Lawrence that are labeled as terrible actresses because movies based on teen-lit are crap.
It's very possible that they are terrible persons and/or dumb as bricks, but if that had anything to do with being a good performer, that would be known. It's very understandable that things you know or think you know about a person can spoil your enjoyment of a film in which that person acts, but again, that's not related to the matter at hand. As for
Lithose
's casting couch implications, they are pretty absurd : I did not go through Brie Larson's whole filmography, but none of her significant film and TV credits have anything to do with Miramax nor The Weinstein Company.
That being said, the metric
a c i d.f l y
chose for his scientific assessment does not lack merit ! Having had to deal for a little while with short films, a format in which bad acting is rampant, british actors were somehow always good ! Maybe not 3000% better, but good.