Would be interesting to know how much they can actually recover from that black gunk - that video didn't really show much more than a big grinder.
I wonder if the occasional NiCd or lead-acid (some walkmans used small lead-acid, also camping lights etc,.) screws things up with contamination.
AIUI the biggest problem at the moment with EV battery recycling is getting batteries to recycle, as they're lasting a long time, and then getting repurposed.