Ass-covering.

The same reason why most huge enterprises buy insane support contracts for every other piece of shitty software: support, and someone to blame when production goes pear-shaped. Because there’s no real management left anywhere, there’s no time to grow expertise internally and everyone just needs that hit of Risk Management (tm), they’ll go to whatever lengths to get it. Oracle is like the ultimate warm, fuzzy blanket where that fuzz is actually mold, it delivers the scared-shitless enterprises from having to think for themselves.