I just saw a headline asking "Has There Been Any Conversation Among The Cabinet Members About Invoking The 25th Amendment?"  

I'm sure there has, but every discussion has probably ended with something like, "but what do we do about Kamala?" or "but Kamala could be worse!"  At this point the primary thing keeping Biden in office is the fact that nobody (Democrat, Republican, or Independent) wants a President Harris.  

Maybe that is why the Bidens picked her. 

 He didn't pick her. 

They don't want to end up fired. Therefore, they keep the status quo.  

 I don't actually think Joe picked her, but it could be Jill picked her to help Joe maintain power and protect their crime family. 

 Jill is certainly in on animating the corpse, but... I'm not sure she's influential enough Ti make decisions of that magnitude. There's nothing about her that is competent...  

 I'll bet Kamala Harris is walking around the White House dropping copies of the 25th Amendment like she's throwing candy in a parade.  Nobody's taking the bait...