That's an interesting perspective on LOTR. I'm thinking that the entirety of spellcasting in the world consists of five wizards and their apprentices, a few ancient elves, and some dwarven toymakers, and the flying beasts in question number in the dozens only. There are no domesticated flying beasts in LOTR. The great eagles are intelligent, and Sauron's fell beasts were unnatural, and bound to the wills of their riders (who had not been active in some time leading up to the events of LOTR).
Yeah, LOTR is far from the D&D realm. The magic is thin and there are few practioners. Gandalf never wielded magic on par with a mid-level D&D wizard.
It's a low magic world but that's not unusual in fiction. Describing high magic is difficult. It's difficult to plot out all the ramifications for one but more practically, it's difficult to discribe it all in the course of a novel. Much easier to have a little bit here and there. Works just fine for an interesting story.
The current threads have me thinking about my own worlds. Bluntly, I don't craft high magic worlds even though I run them as campaign settings. I don't really feel like arguing about it right now (see lots of early threads
) but I think classic D&D demographics and magic levels would dramatically alter most middle-age-ish settings.
So where does that leave me as a ref that feels D&D level of 'stuff' would alter his setting? Well, for starters, neither my players or I seem to mind; so that's all good; it works for us. As a rationale, I suppose you can imagine a little bubble of distortion that goes around the players and adds a locally higher level of magic and critters than is otherwise present in the world.
In the grander scheme of things, maybe I'll work up a setting some day that, per my own vision, does match D&D demographics and power levels. It is do-able but I think ramifications are pervasive. Succession by blood? Not likely, the next level 15+ character will probably take the throne. High middle ages castles? Don't think so; too many ways to defeat that big, expensive pile of rock. Etc., etc.
Before we go too far down that path there are lots of other factors to consider. I think typical D&D encounter rates are far beyond what makes sense in a "real" world. Such threat levels are on par with serving on the active sections of the western front, WWI, without ever rotating out of the combat line. You'll die fairly quickly. But it makes for a fun game to ignore that and I can live with, just as I can live with castles that probably wouldn't be in a higher magic game setting.