If there was a medieval society where magic was only taught within royal and high ranking noble families, would this cause the society to stagnate?
I mean, a lot of technological developments (but not all) have resulted in more balanced and progressive societies. Would the fact that the 'high born' nobles now have yet another way to enforce their hold over the people, to maintain the status quo, result in a civilization that remains virtually unchanged over the centuries (I suppose much like a magically induced dark age perhaps).
Or, seeing as a lot of Victorian-era science was undertaken by nobles (I'm not too familiar with science in medieval times), would the addition of the mystic arts to their repertoire actually bolster the whole 'gentleman scientist' movement and hence speed up technological development?
There are a few similar questions like Why would a magic world be stuck in medieval times? or Must magic be tied to medieval tech? or even one about disease curing magic (which had some interesting points about delayed development), but those were either dealing with four elements magic, looking for reasons why a society might stagnate or based in worlds where magic is commonplace. I know the reason I would like to use, but I'd like to know if it's a plausible reason, if it makes sense.
A couple of ground rules:
There isn't much of a restriction on the kinds of magic used, only that it's commonplace. Somewhere between Harry Potter diversity and Lord of the Rings rarity.
It can be (and frequently is) difficult to perform/energy sapping and can kill you or go horribly wrong if you don't know what you're doing (unsupervised magicians don't tend to last long).
It's closely guarded, not only is it taught only within high ranking noble houses, even then, only a few of them actually become any good at it (that's not to say there's anything special about the nobles, just that they... hold all the cards and besides, a book on magic isn't going to help a commoner if they can't read anyway - which I suppose would further reinforce the status quo)
Very proficient users (kings and queens etc.) are able to greatly improve their health (and maybe extend their lifespans) through the use of powerful magic (much to their children's dissatisfaction - there can be only one king ;)
There is also no reason why modern technology can't be used, it's just that the bulk of the populace isn't educated enough (or at all really) and those that are would rather keep the status quo as it is (the only way to get in power is to already be in power).
So, could all this basically put an indefinite halt to the development of society, or is progress inevitable? Or can royal magicians put an indefinite halt to a society's development in order to maintain their own positions?