Originally Posted by Frozen_Feet
One way to curb this is to give all forms of "magic" defined rules, and make them isolated from each other. (As a side-effect, this leads to catch-all words like "magic" becoming useless in the setting.) This way, introducing one supernatural technology won't undermine existence of all natural technologies. The funny thing is that this approach slowly makes your work closer to sci-fi than traditional fantasy.
I tend to take a science fiction approach to fantasy anyway, thinking through the mechanics and applying them rigorously, thinking through some of their consequences, and making sure that things that aren't magic actually work like that. For example, dissatisfied with how dwarven mountain fortresses could ever produce enough food to feed them, I made most dwarves in a setting live outside the mountains, with the fortresses been just that, fortresses, places to flee in times of trouble, but not the main population centres. One consequence of this is that there is a lot of grumbling and friction between what warriors and retainers who do make their homes in the mountains and the low landers who barge in now and then.