Warframe launched the Xaku Prime update the other day, Baruuk Prime and weapons have been sent back to the vault, and a week later both Oberon Prime and Ivara Prime will re-emerge from the vault. Personally, I was betting on Nidus Prime being brought back in time for 1999, because this is the infested expansion. Maybe after New Year's?
They're also getting ready for the influx of new and returning players coming in for the 1999 hype, including writing guides on...how to get the Excalibur frame? (For the unaware, you can choose it as your 'starter' Warframe at the beginning of the game, and can farm it in less than half a day otherwise, or obtain Excalibur Umbra by playing the story)
First thing that comes to my mind is that they may want Warframe: 1999 to be its own multi-media franchise, they already have the comic and anime in production, and all signs point to future story with this cast of characters + additional Protoframes afterward.
I'm surprised more chuubas aren't streaming Warframe leading up to 1999 next month, because once the hype goes into full-swing near release, it's going to be more and more difficult to make the several hundred hours of progress needed to catch up without burning out. I'll have to keep doing my part in spreading the word, and advertising the 2-views I'm watching while playing the game myself.
For example, a new Warframe: 1999 track dropped last month, the full version from the TennoCon 2024 demo, and it's ripe for covers, if not at the very least interest by more anime women! The Devil May Cry-ification of Warframe will continue until morale improves.