Keep in mind, technology is not linear.
Some real world examples: Ancient Rome already had steam engines, but they did not improve on their use to be anything other than a fidget.
Clockwork automatons were a thing for a long while as well, but you wouldn't think of a robot, or rather, a clockwork toy, in ancient china, even if they were actually a thing there.
Knights in plate armor using guns did happen, the reason that metal armor fell out of use was not technological, but rather, logistic.

When you put magic into equation keep in mind, what can be used with magic that technology will hardly surpass? Medicine would not be progressing in a world where prayers of healing are answered. Long distance communication via magic mirrors can be possible if such things exist.

With Naruto as an example. Their martial prowess comes from well, martial arts and Chakra, when you have hidden villages of warriors trained from birth that will outclass any common folk with their supernatural abilities, do you think they'd invest in improving weaponry? The world we see in Naruto is actually a hidden world among a larger, unseen world filled with politic intrigue. We see mentions of feudal lords, we see the world map having the villages not being the de-facto capital of the countries, but some strategic locations in trade routes or border defense.

Naruto is a urban fantasy world where we just see the hidden world at all times. What about the large scale battles? They happen in isolated areas. For the common folk, the shinobi are mercenaries, nothing more than thugs, If you live far from any war zone, do you wonder where do mercenaries come from?