When New 52 happened, DC mandated ALL toys had to be based off the New 52 design plus, IIRC, renegotiated their deal with Mattel to limit what shit they could do so DC could have first crack at any and all New 52 themed toys.
Mattel survived by doing media tie-in shit (Arkham game stuff, plus Batman movie shit) and trying to move fans into buying their four inch figure line, but largely failed in securing likeness rights for most DC film/TV properties.
It wasn't until Flash came on the air, that they were able start focusing more on TV shit. But even then, they had burnt their bridges with stores, so they had garbage distribution save for stuff like Suicide Squad's movie line
Dark Knight Returns Batman/Joker/Carrie Kelly, Supergirl, Nu52 Doomsday Superman hybrid are warming shelves like crazy and no one wants to order any new ones as a result.
The irony is that they could be re-issuing some of the older DCUC stuff (OG Harley, Deadshot, Deathstroke, Mr Terrific, etc) to sell to casuals as part of the Multiversity line but they won't do it because they are allergic to money.