More speculation
Everyone's worried that no news means bad news.
HOWEVER
Recently, Futurama was announced to return with the original voices. After a few months, word broke that they were replacing all but one of the original voice actors on the series due to disagreements during contract negotiation. During that time, no party (Fox, the actors, Comedy Central) was allowed to hold any discussion nor make comment on the situation. The executives even went so far as to "disinvite" the actors from the Futurama ComicCon panel this year (with a direct stipulation during the panel that recasting would NOT be discussed). However, in the end, after negotiations, all the actors signed back on.
The case might very well be similar here. If Steve or Disney were to comment, then it's likely that one would lose their footing (or even directly violate the negotiation) and have to either walk or settle for less.
The difference of course lies in the fact that this comes directly in the middle of the new Muppet marketing push. You can't have the face of your brand hidden. Futurama got away with only a few blips in trade papers since there won't be any real press or footage until next year. In this case, Kermit needs to be making appearances. He is THE muppet. Even if they replaced a few appearances with other characters - Kermit needs to be showing up. I'm sure Disney would prefer not to change anything so suddenly, but they see Kermit on the same plane as Mickey Mouse (relatively speaking) and he has to be out there - Steve or no Steve. That's the philosophy of the voice-over business and, as much as I like to believe Kermit is "real," he's still just another character in Disney's eyes. WB even has their actors re-audition for the parts (Bob Bergen has said he's needed to re-audition for Porky Pig multiple times over the last decades).
As a performer and entertainment business man myself, I don't think Disney is trying to "pull the rug out from under us." I don't think they're trying to trick us. They are trying to keep Kermit in the spotlight (with someone who may or may not eventually take over the character). If you notice, in both appearances, he says very little. They need his face out there. The voice, in this case, is a secondary concern to Disney. Based on the performance, it seems possible that Disney may have said to keep his visibility to a minimum and not to draw attention to the voice change (whether it's successful or not is another point entirely). You can't have a mute Kermit making appearances at the VMAs or on NBC - but you can have a mute Kermit at a marketing event because he's the face of the brand. So we have someone step in when needed.
Depending on how long these negotiations have been going on, it may be days or months before we hear anything official (or off the record) And if Steve is holding out for more money/time off/etc - the man does so much with the Frog (and I'm sure Disney is planning on making the Kermit appearance schedule more demanding), he deserves to fight for what he feels is fair. And Disney may just be waiting to see how the financial response is to this D23 relaunch - so Kermit may fade a bit from prominence (as we see a AGT Gonzo solo appearance tonight - when was the last time THAT happened?) - doing small interviews and personal appearances - while Disney figures out what they can/will afford - and if Steve's demands can be met or negotiated at that point, things may change.
Hopefully, it's all just typical showbusiness mumbo jumbo in the way. Just thought I'd weigh in my two cents.
Ed
PS Oh - and after re-reading it, "demands" sounds like a harsh word ("requests" would be better, but not accurate to contract lingo) - so I'm not meaning it to sound like Steve's holding out and being a diva. I just mean he's looking out for his best interest, which anyone in his position would need to do.