EDIT: here's the one mention of `aria-live` in the React.js codebase defining it as a valid ARIA attribute for ReactDOM: https://github.com/search?q=repo%3Afacebook%2Freact%20%22ari...
The one mention in Vuejs core to define its accepted values: https://github.com/search?q=repo%3Avuejs%2Fcore%20%22aria-li...
The one mention in the Svelte runtime defining its accepted values: https://github.com/search?q=repo%3Asveltejs%2Fsvelte%20%22ar...
Do people go after these frameworks saying they need to handle breaking screenreaders by dynamically updating content? Of course not. Setting live regions is the responsibility of the web page creator, not the framework.