> Are there other projects with numerous corporate contributors, then, which were threatened or destroyed by poor patches? My perception is that Postgres has a large number of corporate contributors, but they don't seem to be hurting for it.

There's definitely sometimes strains showing. Corporations have often interest in getting specific features in, but don't care that much about maintaining the codebase and/or maintainability.

Definitely causes some strife. I think we most of the time keep it civil enough.