Someone recently brought up the idea that magic, in Greyhawk and 1st Edition, was writ large across the world, but outside the experience of normal people. It's like military hardware in modern America. I'm a private citizen in the northern Midwest; I go years without seeing military ordnance. I read about its common use elsewhere in the world, but it's not a part of my day-to-day life.
Magic in 1st Edition is like that. 1st Edition spends a lot of time on pole arms and poisons, on diseases and the hiring costs of people who'll build you a castle. These are real-world medieval concerns.
Where do you find magic in 1st Edition? It's lost in caves, protected by nighmarish things, rare, exotic. There are "war-zones" where it's common.
Magic in 3rd Edition is much more common. The baseline assumption is that anybody with a couple hundred gold pieces can just walk down to the local magic shop and buy a magic wand. Many of Eberron's detractors look to the commonality, the banality of magic there.
And this change in the perception of magic also alters the way the game is played. If magic is an easy commodity, you can play faster and looser with dangerous situations, because you just bought 50-CLWs-on-a-stick. If you want to do kewl things with boots of spider climbing, you don't need to go to the Silent Hills and confront the goblin nomads, you can just make a pair.
I think I prefer the earlier mindset, but Exalted outsells Tribe 8.