The .com space was cut by about 40% across the board business and technology. Onshore BAs became PMs to give them the authority they were already exercising but they also continued to perform Business Analysis work.
The reason I acted as a PM is because I was acting as a product owner. If something went wrong on my project my boss held me accountable not the PM. I couldn't come back and say I didn't deliver because the PM or Dev had this issue. I was expected to provide the challenges and solutions that my project was encountering across all areas of work(Req., Development, implementation, testing). So the reason I acted as a PM is the project required me to in order to meet leadership expectations. That is the mark of a good PM is no one needs to tell me how or when to do a job. If there is a gap you figure out how to fill it and quit pointing fingers.