system
Given the following post, respond as if you're commenting on Reddit:
human
[General] Why are magical societies so backwards?

By backwards I refer mostly to how almost all societies with magic are more or less stuck in the medieval age.

While some of such societies are placed in a general medieval world, others don't have such excuses. Others are excused by saying that magic mix badly with technology. (but the Weasley car was awesome!) 

The most jarring example I can think of is Thundercats. The tech savvy lizards kicked the lions ass so hard they went from apex predator to near extinction in one day. All because they refused to adapt to technology. Other examples include Star vs Foe where the monsters was starting to get the upper hand by using technology. I'm also peeved by the attitude of wizards in the Harry Potter universe sans Mr. Weasley.

At least in Adventure Time, PB tries to talk some sense in the wizard community but to no avail. The wizards are too arrogant to hear her out. 

So why? Why do magical people reject technology even when their sustainability is at stake?
gpt
Lack of selective pressure. Magic pretty quickly leads to post-scarcity, or nearly so, and also makes you the biggest, baddest power around.

If you don't have any credible competition for a few generations, you forget how to compete. Tech-based societies are built on continual, gradual advancement, however. Eventually they reach a point where they're competitive with magic, and perhaps even superior.

If we consider *Harry Potter*, magic has allowed the Wizarding community to exist more or less undisturbed for generations, but the Statute of Secrecy still exists, because if muggles got serious, their war machines would stand a chance at taking the wizarding world out en masse. And if muggles advanced to the level of the Federation, a wizarding victory actually starts to seem remote.