b) I really can't speak for said teachers. But my observation is they are pretty busy are busy in the dojo working on these sorts of things and teaching them to their students. I can speak as a student and say that my observation so far of my own teachers is that they are most certainly breaking some new ground in the matter of introducing these ideas earlier in training than it appears is traditional...
Meant to come back to this part sooner, but got distracted and spaced it.
At the moment, a number of teachers are "working on these sorts of things and teaching them to their students"... or have "already been teaching these things for years". Let me take this thread as an opportunity to give an idea what I look for when I meet some teacher or student for the first time who claims that they are already doing these things.
The first thing I look and feel for is whether they have any built-in jin/kokyu-power to their movements. It can be felt at a touch and there's no way to fake it to someone knowledgeable. If someone really has this sort of skill already imbued well enough in their movement, they should be able to easily duplicate the type of "ki test" that Tohei advocated. If a person cannot do these simple things, then all the other "advanced knowledge" they have goes out the window. It might be some cool stuff, may strong stuff at that... but it's going to be based on some partial or incomplete understanding of what internal strength is.
The demonstrations that Ikeda Sensei is doing are pretty clean instances of kokyu/jin ("jin" is a little more refined term for the forces being used; "kokyu" has a slightly more advanced implication that gets away from the simple thing I'm trying to say). Until good kokyu is developed a person doesn't have good kokyu, right? That means that all the "techniques" that are being done by them as "internal strength" are not really internal strength.
So the first thing I look for is "how good is your basic kokyu/jin?". If it's not there, everything else goes out the window. I.e., both Tohei's and Ikeda's approaches of just basic kokyu/jin/ki-strength are what people should be focusing on. Otherwise you have to go back later and relearn a lot of stuff.