If I’m someone who just wants to get an app out the door, then I’d argue that not being able to gracefully bridge to other paradigms when there is a gap in what is available under a reactive pattern is by itself a problem (an ecosystem problem). That’s why I use React. Despite the issues with bridging to non-reactive abstractions, it remains a useful pattern.

Others may be more concerned with the applicability of the pattern itself.

This is not unlike integrated automatically GC'd and non-GC'd code.

The gap can be bridged for granular reactive systems as it can be for React, provided the reactive system is well designed.