Counterpoints to show that it is just a compromise: The complexity of unicode, collation, encoding, translation, language.
However you're 100% right!
Our application actually used text files on a network share with an indexer over the top as the database engine a long time ago. It worked really well and integrated with NT security and file locking for concurrency control, plus it was very easy to back up. A work of genius. However, NTFS doesn't scale well with lots of small files as it stores them in the MFT so it fell off a cliff eventually.