I can't find Philotomy's explanations of this - but Windjammer's link to the Mearl's commment is very interesting in terms of what players _do_ in the game - then and now.Regarding the OSR:
I hope I'm not implying a directly causal relationship, here. What I am suggesting is that the edition wars, by being largely exercises in comparison/contrast, have brought older styles of play to light. It was through threads here, for example, that I came across Philotomy's explanations of how the expectations/sensibilities of newer games/versions often act as impediments to understanding the rationale of older styles (I hope I'm not butchering his stance too badly here). Similarly, it is through links provided in such threads that I've come across blogs such as Grognardia or Jeff's Gameblog.
While I would hesitate to assign direct causality, I think each contributes to the other.
Does this make sense?
In narrative terms, I think it's amazing that OD&D so quickly found a consensual pseudo-mediaval world that people "got" so they could play the game. My friends and I knew Tolkien, Arthurian romances, Robin Hood, Star Trek, Mission Impossible and some European history but we grasped the idea of the generic D&D setting without ever having read Lieber/Vance/Moorcock. I know it's been said that the roleplaying concept grew from the community of players depsite the OD&D rules not because of them. [1]
I can say that while I've happily run trial 4e games for my 8-year-old son, I do find the power level of starting characters not exactly to my taste. However, I realise that 32 years ago I grasped a game where my character started out like a hobbit in Lord of the Rings in which boys go out on an adventure which makes them men. My son, not only generally lives in a post-D&D world in terms of cultural influence, but specifically he likes Power Rangers, Lego Star Wars and The Sarah Jane adventures (We can share Dr Who). So - his default idea of "Heroes can do this - ...." is different to mine and _possibly_ better served by 4e.
A previous poster mentioned the possibilities of playing with the grandkids and (IIRC) how that may be changed by rules changing over the years. But, the rules may just reflect the latest idea of what being a hero is - and that 's a "cultural" (? - there's probably a better word) divide between the generations as much as anything else.
Tangentially, to this - I liked the original Gamma World and we had fun with it. I think its return is interesting. I also think that WoTC may have realised that the contemporary consensual idea of "this is what heroes do ..." is so little linked to a pseudo-medieval world fantasy world (think BioShock, Grand Theft Auto, Call of Duty) that quite large jumps in the setting might be survived with the games ruleset that is - power A/power B/ Power C with some flavour text.[2]
Actually, given current TV trends, some post-apocalytpic vampires with zombie friends need to be added to the Gamma World mix (both could be a mutation ...).
[1] This is not meant to be an insult to any fan of OD&D - and this reflects comments in the UK fanzine community in the mid-80s that I think were insightful.
[2] IMHO that's the strength and weakness of 4e. I admire its design with some reservations about its feel - FWIW.