Here's why I'm thinking Mattel is a big part of this:
Mattel is the master toy licensee for DC. They pay big bucks for a certain amount of exclusivity and don't like having their toes stepped on, rightfully so.
Their agreement includes 6" scale figures, a scale that DCC had been avoiding, preferring 6.75" scale figures since the DC Direct days... until DCC launched this Animated line. Since Mattel wasn't offering product based on that particular property, isn't wasn't an issue.
Then DCC launched their Icons line, also in the 6" scale. At that point DCC was offering many of the same characters in the same scale as Mattel, even in some of the same markets, with the advantage of not having to pay any licensing fees at all.
Mattel finally put their foot down when they were planning to release movie and television figures at the same time as DCC. Reportedly, DCC's Legends of Tomorrow Atom figure was delayed only to give Mattel first dibs at getting their own version to stores months ahead of time. Of course everything was reported as being considerate and cordial but I suspect Mattel execs were getting pretty peeved that DCC was digging into their marketshare, offering competitively priced product to the same "adult collector" demographic.
Inexplicably, DCC decided to stop offering single figures in the Animated line at their opening price point. Collectors were told that #41 Batgirl was going to be the last single-carded figure and that they were leaning toward multipacks and deluxe offerings like the Expressions packs. None of those SKUs have an MSRP for less that $50, twice that of Mattel's opening price point. It seemed odd that DCC would suddenly choose not to offer in-demand characters like Scarecrow, Poison Ivy, Mister Freeze, and Killer Croc as single figures but they justified the $175 GCPD 5-pack by insisting it was the best way to get a character like Montoya to collectors.
But then they made the same decision with their 6" scale Icons line. They've gone from offering single figures in the $28 range to offering a multipack like The Death of Superman for $75.
All that leads me to believe Warner Bros. Consumer Products went to DCC and said, "Hey! You have to knock it off with the 6" scale figures! We can't have you pissing off our single largest licensee." DCC's decisions seem like a reaction. They've been reined back in, there are new rules in place, and they're offering product the best way they can. They've even resurrected the 6.75" scale Essentials line so they can offer figures in a scale that doesn't compete with Mattel's.
I'm actually expecting Mattel to take note of how much interest there is in this line and announce their own offering for Batman: The Animated Series in time for the show's Blu-ray debut.