I suspect that they will probably still favor custom feeds over hashtags / hashtag feeds. I wonder instead if there would be a good way for them to surface a "trending" equivalent for feeds - which feeds have had the most growth in usage (posts, saves, likes) over the last x number of hours.
Oh definitely. @nowbreezing.ntw.app , for example, does a trending word thing already. Wouldn't be hard to do that for hashtags - probably even exists already somewhere.
I've actually included @nowbreezing.ntw.app into my app @skeetsapp.com for iOS / iPad OS because I found it super useful.
Skeets already supports hashtags. When clicking on one it triggers a full term search on the meta tag. It also lets you add hashtags when composing a post.