I agree with this. I just think that the definition of Roleplaying (as I use it and as the D&D books use it) is broader than you've been claiming in this thread.My only intent was to show, in accordance with the subject of this thread, that I don't think that the meaning has substantially changed from 40 years ago. There have been refinements, corrections, better formulation, a lot of advice, but I don't think that the core concept has changed a lot.
While I enjoy playacting as part of my RP, it's optional. Whereas unless I misread you, your opinion is that playacting is absolutely essential and that anyone who doesn't isn't actually roleplaying.