Dang, too bad. I heard the MacFarlane stuff was good?
I'm quite fond of them

I collected some DC Mattel stuff back when I had a larger Marvel Legends collection, because the Mattel stuff was also six inch scale, so I could mix and match, corporate mandates be damned

Thing is they just weren't great? Marvel Legends hardly blows anyone away- they're perfectly cromulent just rarely more than that- and Mattel's stuff didn't even reach that level.
2019 was a bad time for DC and Mattel. Mattel was hit hard by TRU closing in the States and DC's film series was lagging way behind Marvel while the MCU was firing on all cylinders.
These days, DC is hardly lighting the world on fire, but the MCU is at the nadir of its popularity since its height while people seemed to like The Batman, and have genuine hype for the new Superman movie. Also, Marvel Legends just seem unambitious? Like take a modern day Marvel Legends toy and a GI Joe Classified toy and the latter just laps the former. Both six inch collector oriented action figures, both made by Hasbro, but the polish on the figures and accessories just seems evident on the GI Joe stuff it really isn't with the Marvel stuff.
Maybe it's just the the action figure fandom circles I run in.... but the vibe I've been getting recently is that there's a lot of fatigue behind Star Wars Black Series and Marvel Legends (my husband is just not collecting Black Series anymore and he's a huge Star Wars fan).
Meanwhile McFarlane kind of broke the scale, because their stuff is seven inches and not six, but has otherwise been well received. There's Batman Fatigue, sure, but like... are we gonna pretend Mattel didn't spit out new Batman variants at every opportunity either? Of course they did. That one's not on McFarlane, it's just that Todd is very vocal about his Batman fandom so ofc it gets that attention.
Again, the vibe I've gotten is that McFarlane's handling of the DC collector figures has sort of corresponded with an uptick in interest in the DC brand after years of Marvel Legends kind of being the undisputed master in the mass retail collector comic line space.
I personally think they're great. No, they don't scale with Marvel Legends (though they do scale with Marvel Selects), but they work in a sort of meta way, DC doing its own thing and all. And on top of that, they're just good toys. I've gone in on McFarlane DC stuff, as well as Jada Toys' six inch Street Fighter figures, and it's not just the vibes I'm around... Hasbro's six inch game is really lacking compared to both.
I'm bummed about this news, because I do really like what McFarlane's done with the DC licence, and I'd dare say they've helped revive interest in the toy brand. I'm not sure if this is WBD just wanting to consolidate all of their toys under one label again, if Todd said something to piss of WBD execs (always a real possibility), or if Mattel just had a better sales pitch/offer, but it is what it is.
I'll definitely check out what Mattel has to offer this time around. Their last go wasn't really my cup of tea, but they have done pretty well with Jurassic Park, WWE, and MotU Revelations... so hopefully their new DC stuff is likewise as good.