I think it's important to distinguish frameworks from libraries. With libraries, your code is the caller; you can compose things as you like, including with you

I think it's important to distinguish frameworks from libraries. With libraries, your code is the caller; you can compose things as you like, including with your own code for cases not covered by the library. But with frameworks, your code tends to be the callee; you must conform to (and are thus limited by) the assumptions the calling code has baked-in by the framework authors. My sense is that the pain from this inverted directionality is what drives these bespoke frameworks.