Missing songs links between listenbrainz and musicbrainz

As explained in Tracks that you might like, only songs that are recognized in the mb db will be use to generate recommendations.

I noticed that a lot of song I listen aren’t recognized, witch is strange because I add most of them to the db…So I check and in fact there is various who are in the mb db but the link isn’t done witch listenbrainz…

How is that ? Missing information in tag ?

exemples :

youps : solution here : Can the ListenBrainz db be updated to the latest MusicBrainz db?

You need to use a scrobler which submit MBIDs…Is this alway true today ?
Why not guess the MBIDs from artist and song tag ? is this on the roadmap ?
If not is it a problem to use https://github.com/web-scrobbler to fetch mbids (from the api with artist and song) before scrobbling ?