Crimson Engine explains “What Does a Producer ACTUALLY Do?” (2018/2/13).
The producer runs the entire infrastructure to make the movie, but does not provide money. The producer uses money raised by others, which are often financial entities on Wall Street. The producer hires (and more rarely fires and replaces) the director.
He discusses the Executive Producer, which is a more flexible concept having to do with supporting the project and raising money.
He explains a PGA Title, which requires being on the set for 80% of the set days.