The problem commercial businesses have when it comes to open source is that you might be able to reduce customer take up, by you can't compete with it like you would other businesses. In the closed source world you can purchase a company and shut down its product and thus kill off the competition.

As Microsoft have found, with open source software, that's not possible.

The other unfortunate thing for Oracle is that when they attack Postgres they have to publish lists of competitive advantages. All this does is give Postgres developers a todo list, and they then work towards implementing the features that matter.