> you couldn't afford to spend weeks or months learning the idiosyncrasies of your new codebase especially when it came to state management. That's the main problem frameworks and libraries were solving.

Not really. Frameworks are usually created to avoid boilerplate and provide some nice scaffolding to support you while you’re coding the business layer. And a lot of them do smooth over accidental complexity, even though the architecture is generic and may hinder you in the future.

But the learning curve still exist, as most of what you interact with is custome codes, modules and components.