The new Journal app that
comes with iOS 17.2 is basically
Jotunheim (and a jillion other journal apps), except done super slickly by a team at Apple.
Jotunheim is an app I released in 2011. For many reasons, it did not take off. I think I set the price at $2. It had a total lifetime revenue of around $30.
I made it without bothering to do any research about whether anyone would want it. I just assumed that because I wanted it, thousands of others would, too.
Apple most certainly did research into this before starting development. I do wonder what they found out, either in terms of existing demand or demand they could create and what leverage it will provide them.