...seems to have stopped almost completely, I'm not sure why some still work.
So all those add-ins and apps to save YT videos no longer work, unless you get lucky and the clip you want permits this. 4 out of 5 I tried yesterday didn't work.
So there is surely a workaround, because for-pay software. I just haven't figured it out yet.
Oh and I'm not going to debate the whys and why nots of doing this here.