This is probably the avenue to shut this down. If funding is contingent on making the publication freely available to download, and that comes from a major government funding source, then this whole scam could die essentially overnight.

That would need to somehow get enough political support to pass muster in the first place and pass the inevitable legal challenge that follows, too. So, really, this is just another example of regulatory capture ruining everything.

i hear you, but this leaves this massive gaping hole very quickly filled by predatory journals

the better solution would be journals created and maintained by universities or other institutions with national (or international, like from EU) funding