The magic of this world is unrestrained. Once you know the words of spells, you can cast them without restraint. So long as you can speak, at least. All magic is oral. But this poses a challenge for societies. While magic allows societies to develop rapidly, they also implode quickly. It doesn’t take more than the discovery of a few spells for rogue wizards to destabilize a society. One wizard with ambition and some social skills can rally angry lower class peoples into terrorist organizations and start fighting for power. This likely destroyed many prior civilizations. It could even be the real reason the history of the world is steeped in bloodshed and the technology stuck at medieval level. No society has been able to restrain magic enough to advance beyond a certain level. Hence the world is so polarized, with extreme potential and extreme destitute.