Actually implementing persistent storage for simple apps isn't that hard, especially for a big corp. Personally, I was using LLMs coding capabilities to create custom single-file HTML apps, that would work offline with localStorage. It's not that there aren't good options out there, but you can't really customize them to work exactly how you want. Also it takes like half an hours to get what you want.

The only downside was not being able to access the apps from other devices, so I ended up creating a tool to make them online accessible and sync the data, while using the same localStorage API. It's actually pretty neat.