To add to what @lichtjaeger said, also keep in mind that webpack, grunt, etc. are not just used for bundling. We also use them heavily for transpiling these days. HTTP2 won't help with that. So I think they will still be relevant at least as long as we are transpiling code to use features not widely supported in all browsers.

There is an article.

In my opinion it depents on loader and server implementations.

Example: The js-entrypoint imports some modules and these imports more modules. If the server is clever enougth to detect this modules and send them with http2 push, it is ok. Same for all html src atributes. (a win for web-components)

But if there is only a single js-entrypoint you can still benefit a better compression and tree-shaking using a bundler.