General Discussion

Free database platforms like Postgres or even Oracle's own MySQL (community version) are great for what they are (we use them all the time for client projects in our small shop) but they lack a lot of features that truly big companies need in a database system. In a nutshell, they only scale up to a certain point before they fall over on you or don't (fully) support a data format that you want to be able to store in your RDBMS.

This is not to speak to whether full-fat Enterprise-level Oracle should be considered overpriced (it does seem so to me as well), but it does scale up to support HUGE organizations with extremely complex and large-scale data storage needs in a way that the free stuff cannot