Just saw a few creators building better UI versions of HN.
I realize now, that one of the important factors that keep HN's audience selective is its simple UI.
IMO if we put the design and UI/UX elements of modern social platforms, it may start to attract a wider audience which certainly is not the intent of this platform.
Amazon.com is the ugliest e-commerce site going, but they aren't worried about losing visitors to Wayfair.com, because they're not competing on looks.
Same thing with HN, they are not in direct competition with any other site. The high quality of discussions (thanks to moderation) helps the site show up in search engines, which is how most people discover it.
There are lots of alternative front-ends to HN, those are personal projects and not done to try to boost HN traffic, just to improve the UX for regular visitors. For example I use a browser extension that adds additional menu items to the HN orange bar, like "shownew".