It's an innovative and interesting idea. But just to play devil's advocate for a minute, for this to get widespread uptake, the way it is implemented would have to be agreed on as being the right way, by a lot of people (i.e. users). And there could be lots of different ways of implementing what you describe, with variations, which makes it more difficult (though not impossible) to get accepted widely, compared to the existing plain pipes and passing data as text around between commands, because not much variation is possible there.