See, the thing with this is that I, as a reader, would think: but why not just use magic? That'd be the intelligent thing to do.

That's the problem with high magic settings. There is no reason for technology as we know it to ever exist because magic would have taken over completely. It would even be more widespread than technology because every one of these settings inevitably has more magic users than the real world ever had master craftsmen and inventors, given the same relative time period.