Earlier quoted context omitted.
I worked at a company who re-implemented the entire Dynamo paper and API, and it was exactly the same story. Completely eliminated all my illusions about the supposed superiority of distributed systems. It was a mound of tires held together with duct tape, with a tiki torch in each tire.
Did they have a spare 100 million hanging around to burn? That seems pretty ridiculous. Why did they not just run cassandra?
Not Invented Here can run very deep in some branches of an organization. Depending on how engineering performance evaluations work, writing a homebrew database could totally be something that aligns with the company incentives. It might not make a single bit of sense from a business standpoint but hey, if the company rewards such behavior don't be surprised when engineers flush millions down the tube "innovating" a brand new wheel.