That might not have been the best choice of words. There just seems to be a comparative dearth of discourse on the Right to Dream. Well, Edwards does say that it’s a fringe interest, so perhaps I shouldn’t be surprised by that.
But not fringe in RPGing! He thinks it's been the predominant mode since the early-to-mid 80s.
One oddity of his framework is that he groups two things together under the "right to dream" that most RPGers see as quite different: RM/RQ/HERO-esque "purist for system"; and DL-ish/CoC-ish "high concept simulationism".
He groups them together because, in his view, both prioritise
exploration as an end in itself: the former is exploring the system and its ramifications/outworkings (like your "experiment" metaphor upthread); the latter is exploring (without further metagame priority/provocation during play) the setting and/or characters and/or situation.
(A parenthetical elaboration on the second parenthetical remark in the previous paragraph: of course there is a metagame/genre reason why in DL we have characters like the "odd couple" twins, the anguished half-elf whose former lover has turned to evil, etc. But the system has no way for those metagame concerns to manifest in play itself - eg there is no rule whereby Tanis's player can get a bonus to an action because he is trying to save Kitiara from a fall from her dragon. Pendragon still counts as simulationism in Edwards' view because the influence of passions and traits is driven purely by system logic rather the injection of metagame priorities into resolution: the contrast would be with spiritual attributes in The Riddle of Steel or with bonus dice from emotion/passion/relationships in Prince Valiant.)
Now here's my metaphor/analogy-expressed conjecture as to why Edwards' grouping of these two modes of simulationism causes so much drama and pushback among so many RPGers: suppose someone turned up among a group of motoring enthusiasts who, moreover, have only the vaguest awareness of and interest in yachting and flying. And suppose one told them that the best explanatory framework for vehicles draws three fundamental distinctions: planes, boats and automobiles of all sorts (cars, motorbikes, trucks, etc). Those enthusiasts may well (i) find the proposed scheme to unduly prioritise some niche interests, and (ii) to miss all the fundamental distinctions (eg between station wagons and sedans and 4 wheel drives/SUVs and utes and various sorts of trucks etc, all of which serve very different purposes for their various drivers, handle very differently, etc).
If, as a RPGer, the main approaches you're familiar with are (i) system-driven sandbox, or some development of that in the RQ or RM-esque direction and (ii) "story"-focused RPGing like DL, CoC, VtM etc, then a classificatory scheme that bundles them together as various ways of prioritising
exploration will seem unhelpful, and like it misses the point. This is why I think Edwards work on "the right to dream", while very very insightful, and highly applicable, has had relatively little traction among those whose RPGing it describes.
