That would be easy, but like so many things it isn’t simple. 🥴 

Consider a discussion with, say, 2000 replies. You can’t load them into the same page, so some type of paginate, infinite scroll or partrial preload has to be used. Notification may be about a 654th comment in that thread... so when you link to it inline we’d have to load it along with some of nearest context replies (Parent comment, childs, etc). Simply linking to the post isn’t effective because it’s hard to find the comment in question. 

So, a separate page for each comment linking to the parent content is the most simple option, in fact used by Twitter and Facebook in many instances. Doing it in a considerably better wat would require something  similar to what’s FB does - launch a mini ReactJS app object for each comment section (and there may be many of them on each page, like in Feeds) that can be manipulated extensively without significant performance burden. Current Ajax comments are not particularly good for this at scale. 

We thought of this a while ago and the JOT program was in part inspired by this challenge. The new “live comments“ that we are working on will have direct in-page linking.