This means that in theory the backend/runtime can be replaced (and was replaced ones from React to Preact (0.7.0 -> 0.8.0) then to use hooks and signals instead of class components (0.19.0 -> 0.20.0), and the code will remain the same.
This has one drawback which deters framework creators from choosing the language since there is no reason to innovate on something that is already "done", which leads to fewer people using it in general and hinders adoption, but I'm still optimistic.