And here's my point: You don't know that they definitely would. Go with "could," and I'll accept that you've got a point- but it's also possible that their rejection of magic could carry with it a bias against other experimentation, leading them to not develop anything on their own but to use bows like the rest of Tamriel. :shrug:
I see your point.
I failed to mention i am basing this on a real life example. I know of a major religious group existing today worldwide who opposes magic in any way, form or shape and shuns away from interacting with anything even remotely associated with it.
But your point about refusing experimentation doesn't ring true.
Their refusal of magic would much more probably be based upon its divine/diabolic nature - as is the case with the real life example i have in mind - thus inappropriate for humans.
So they would be forced to develop ?natural?, mechanical means of self defense against those who do practice offensive magic. Probably leading to gun technology, i'd say.
I should add this is by no means a concern of mind. I really don't care for guns in SKyrim. I just think there could be a rationale behind them, unlike what some have suggested.