PRs might have been an open source innovation, but not "trusting" your developers has a very long history that predates OSS and PRs. The way it was done was to

PRs might have been an open source innovation, but not "trusting" your developers has a very long history that predates OSS and PRs. The way it was done was to have QA check your code, usually as part of a release. I think PRs became more popular in non-OSS because of CI/CD and agile methodologies.