Funny, I was having a conversation about this just the other day in another forum.
The wonder derived from the contrast of magic is not about the presence or absence of magic in common places, but rather the how the magic encountered compares with the already established magical norms of the world.
This is actually a key point, I think. In this conversation, multiple people have offered examples of how a high-magic setting could in fact be wondrous and I notice none of them involve spells that are already in the PHB.
Whatever magitech we're talking about (I have never read Eberron, so I'm going off what others have said here, and a handful of things I've heard in the past) is not boring because it's high magic
necessarily - it is boring because it takes what we already know
a step in the wrong direction. D&D magic is already toeing the line of being boring! It's borderline science: reliable, transferrable knowledge that works the same way every time. Every CLW heals about the same amount of hit points. Even
resurrection works in a manner that can be described in a few paragraphs! Obviously, it has to be this way in order for the game to work - the players need to know what their tactical choices mean. I am in no way objecting to this, nor pointing out anything we don't already know.
But what we must fear doing is pushing it any further in that direction without a really good reason. As far as I can tell, the magic-as-technology settings don't add any interest or excitement to how magic is used. They simply ask "what if we cast all these spells in the book a WHOLE LOT?" Well sorry pal - all of us here can think about that just from reading the PHB. It's cool when I first get a wizard to 11th level and start my own
Wall of Iron mine - the first time, anyway. But asking me to buy your campaign setting so you can point this possibility out to me does not count as much of a contribution.
Contrast that with:
I mean, if noone knows if the gods exist, and clerical magic is a matter of faith, and the seals that bind the demons of the first age are crumbling and the secrets for maintaining them are lost, and the underworld is thought to be the body of a great dragon, and its tunnels open up into strange worlds and demiplanes, and the dream masters are trying to transform your society by invading the minds of sleeping leaders, and dragons and fiends are engaged in a secret cold war for control of the Great Prophecy...
I'd play in that setting. This took a DM sitting down and thinking "what kind of cool shit is going in my game?" What I
suspect everyone is pointing at with these comments is that it comes down to DM effort. If your magic shop has the the
Blade of the Dawn for sale, but only accepts payment in wights' knuckles, fairy wings and vials of mercury, that's a damn sight different from dragging a couple 5-gallon pails of gold through the city streets to buy a
sword +3. They are both high-magic item shops, but they function very differently. One can be predicted just from reading the rulebooks, and the other cannot. I think that's what makes it wondrous.
This is a lot of work on the prep side. Since time & effort are finite resources the more magic you have in your setting, the more will naturally be generic. For this reason, low-magic is a hell of a lot easier to handle. You want to come up with a name, history & legends surrounding every goddamned magic item in the inventory of that 12th-level fighter, the guy who goes toe-to-toe with dragons all day? What about all the items in that magic shop (especially knowing the PCs don't have enough money to buy all of them, and some amount of that prep is a guaranteed waste)?
I sure as hell don't. But I could do it for the stuff the party finds in my 1st-6th level game where "+1 or better to hit" is a rare and frightening monster ability.