At the time female comedies weren’t as known for being raunchy, and Bridesmaids has a scene where Maya Rudolph gets diarrhea in the street.
There was no gauge for how audiences would respond to the movie, and if it didn’t do well, Hollywood simply could have passed on any other r-rated, female driven comedies, citing budget concerns.
To be fair, The Hangover really was a litmus test for r-rated comedies in general, and it paved the way for the studios to be more comfortable making r-rated comedies, including Bridesmaids.
You would think every movie would stand on its own merits, but that not always how Hollywood works.