People learn from their mistakes, they get more experience. The more you revise it the better it gets and the better you get at doing it.
If their GOAL was to make a new kind of database that would make sense, but I'm not.
Why should I spend time making a new database format when my goal is FAR from making a new database format. It just doesn't make any sense.
If people always made everything in their projects from scratch no one get anywhere, or at least as fast.
Edit to your edit
I'm not sure why you're freaking out about this, people should do whichever is easier for them. Learn a query language or make a bunch of arrays?
I'm confused on why you would suggest trying to make a whole new database system that can be written to, read from, saved, and loaded when I already stated that I was going to use SQL.