alt Hacker NewsSexism is defined as prejudice or discrimination based on sex.
Prejudice means to form an opinion before the facts are in, but if the facts are there and support you, it is not prejudice.
Discrimination is fairly broad, but in this case can be summarized as preventing someone to get a job due to who they are as a person.
Having established what these words mean, I think it is difficult to entertain the idea that sexism played a role in women being underrepresented as founders in the 2020s. Also, as I have no data on this, I am not sure if the claim of underrepresentation is itself a prejudice or not.
How many women try and succeed? How many men try and succeed? I do not expect to have the percentage be vastly different in the last ten years.
If you don't believe that a system can be set up in a way that discourages certain people from trying, then sure, you can only measure the success of people who try. I don't find it plausible that there are no structural influences on whether people try to participate though.
I'm also not sure why you're bringing up "in the 2020s" as a counterargument against the idea that Theranos was not an outlier at the time it operated when it shut down in 2018.