Medieval Stasis

I've always found it weird that most fantasy worlds seem to be permanently stuck in the Middle Ages. This situation is common enough that the website tvtropes even has a name for it: medieval stasis. This trope's prevalence in the fantasy genre is most likely the result of Tolkien's stories set in Middle Earth, where in the thousands of years after Sauron's initial defeat human society and technology remained largely stagnant. Since then this trope has seemed to dominate fantasy, making technological advancement coincide with magic the rare exception rather than the norm. Another part of medieval stasis seems to be the fact that very few fantasy settings make use of gunpowder/firearms in order to keep technology at a less advanced level, even though both actually existed (albeit in a primitive state) in the real medieval era.
 I've usually found the justification that magic use has stifled creative growth to be rather weak, as even today when we have luxuries that would be considered sorcery by earlier generations humanity is still pushing the limits of scientific thought and technological development. Also, only a few series like Piers Anthony's Xanth novels have magic utterly saturate the setting. The rest tend to have magic users be rare, keeping everyone else relatively isolated from it and presumably be forced to rely on technology.
 I think the presence of magic would actually increase the desire and speed of technological developments because of the arm's race for dominance it would create between those who can use magic and those who cannot. When there's the possibility of fighting a wizard who can blast lightning from his hand like it's nothing, you're going to want to be sure you have a cannon or rifle to take him down from as far away as possible. Better yet, the presence of magic could be used to aid technology as shown in Terry Pratchett's Discworld series where the resident wizards have created a magical computer and cameras are powered with miniature imps.
So yeah, there's my little rant on medieval stasis. When I write a more traditional fantasy story, I'm going to make sure to include lots of guns and other technological advancements that would fit with the time period I'm trying to evoke.