I don't get it. The ability to source some js and then add a wherever you want just like it was a built in element is one of the best things to ever happen to web design. This is what we should have had ten years ago, not the post-jquery framework madness we have now.
I do think it was dumb that got removed though.</p>
Is it okay for you if you save a webpage but no contents are saved in fact? Do the test and save in HTML (with the native "Save as" feature) this page [1]. The saved page will be almost empty because it's made of web components. This is an example of issue that should be fixed.
[1] https://bugs.chromium.org/p/chromium/issues/list
Edit: This might be fixed, see my first post https://news.ycombinator.com/item?id=22604632
Are you sure that's why? It seems possible that the issue is how the data is being loaded. How did you confirm that web components are the issue with loading that page from a saved file?
Yes I'm sure. It was a bug in SingleFile [1] and to fix it (I'm the author), I must add a JavaScript script in the saved page to deserialize the shadow root contents that are missing. It means that JS is required to view this saved page correctly.