If a bunch of guys get together that are interested in ki/kokyu/qi/jin skills, everyone will be at different levels, will know some variations that perhaps others in the group don't know, will have different "favorite training methods to develop this stuff best", and so on. That's only natural, right? But the basics will be the same because they must be. Same thing with all these martial arts: Chinese, Japanese, Indonesian, Indian, Thai, Malay, etc...... everyone will have different takes on a lot of things, but the basics are going to be the same; as all those similar demo's should indicate immediately.
Incidentally, despite the different appearances in different arts, different breathing methods, etc., the basics are the same everywhere.... AND it should be noted that even the oldest examples we have definite records of (like the paintings from the tomb Mawandui: http://www.showchina.org/en/olympics...08/t121902.htm
) are the same basic stuff. The knowledge is widespread AND it is pretty ancient. The practices within Aikido reflect a continuation of a knowledge/skill set that is literally thousands of years old. Hence O-Sensei's references to ancient theory in his douka, etc. Is the essence of something simple like pushing the same? Sure.