I don’t know why the subject of ISSN keeps coming up.
1. ISSN assignment have NEVER been about content or quality. As long as it is serials, it can get an ISSN.
2. It is not even physically possible to review every entry. Some ISSNs are assigned before first issue published.
Vanity journals and books have always existed. It used to be in the humanities (There are many pay to publish poetry journals and monographs for literary rejects). Now it is in the sci & eng because of the OA movement. …And they always had ISSNs and ISBNs.
If there’s any chatter about reviewing each journal that request an ISSN, that is definitely news to me.
