That's not exactly the sort of team where you'd expect MIT Ph.Ds to work. It's precisely big teams of mediocre people who run into issues based on not knowing exactly what the database is doing and how it's supposed to work that lead to data corruption due to misuse. It's almost always a boring problem (e.g. retail business software). It's almost always a clunky commercial "enterprise" solution (e.g. Oracle). It's almost always a big team. I'm not sure if I even need to go into application engineers -- you put your best and brightest into the core product, and solutions typically gets those that can't quite cut it there.

Regardless, your comment was about PostgreSQL, not Oracle. Oracle is a giant piece of software written by a corporation with over 100,000 employees. Something like that is bound to have bugs, and it has bugs indeed. Data corruption with Oracle certainly happens. PostgreSQL is written by a small, ultra-elite team. It's a much smaller codebase, so an expert developer can understand how the whole system works. There's a big difference in robustness between the two.

Of course database bugs can cause corruption. I've certainly had MonogDB eat my data. But the level of robustness of different databases is very different. There are many databases which are essentially bug-free. If you're losing data with PostgreSQL, odds are you're the one losing the data, not PostgreSQL.