ptolemy18 said:
And it occurred to me... the easiest way to reduce the availability of magic in your games is simply to assume that everyone in the campaign world is fairly low-level. That way there simply aren't as many people who can create powerful magic items or cast powerful spells.
Well, it's only the easiest way if you don't take the challenge ratings seriously, which I think is one of the handiest tools available in the game: although it doesn't make matching encounters to groups a perfect experience, it is a much better system than my guestimating used to be.
The levels of magic are built into DND the way it is enumerated in the core books. If you want to lower magic, you should lower XP progression by about the same ratio. Else you have to tinker with ELs, which I think is harder.
That said, magic levels and base levels of play are one of those salt to taste inconsequentialities. I use a 5th level base in my game, from Sean K. Ryenolds nifty little essay about NPC progression. I also personally dislike the old skool, Eb-Ironic "heros are the only special people in the world, except for villains" take on adventuring. Although it is very classic, very medieval, it sort of seems like it's handing everything to the PCs on a silver platter. Also, it's too hard to for me to suspend disbelief to the point that all the world ending threats haven't ended the world before the four guys represented at my table get to them. It's like the Justice League comics, where every world ending threat comes just in time for the League to handle it. Unless you want to bring in a guest star to do so. At a certain point, there's no world there, just gobs and gobs of story. And I like world building.
So, my "realistic" magic world has lots of people of moderate power, fewer people of low or higher power, and cosmic regions where PCs handle the few epic level threats that actually come along. And the PCs work within that framework, not outside of it.
Where do magic items come in? Well, like Eberron, I run a sort of Industrial Age magic, though many of my items are alchemical in nature. I do this mostly to keep my game in line with the CR system, but also because I like the baroque idea of fantastical technology. I do read fantasy and comics, after all. Quite a bit. But Eberron itself sort of voids the generality that you can make a low magic world with low level PCs: it also uses the Special PC assumption, but has altered the structure a little so that there is lots of low level magic. Go figure.
In the end, it's what you want. To an extent, it is also what the players want, and every player wants to play something cool, with cool abilities or cool stuff. There are no games without GMs, but there are very small games without players.