Question

Why did the rational way of thinking, taught by Aristotle almost die by the 300 AD?

Answer 1

Because by 300 AD, Christianity, which promoted religious thinking, instead of rational thinking, was already spreading over most of the Mediterranean World, which was the same as the Roman World, since the Roman Empire dominated the totality of the Mediterranean.

In fact, only 13 years later, in 313 AD, Constantine, the Roman Emperor, decreed the Edict of Milan, which made Christianity the official religion in the Roman Empire, starting the period of Christian dominance in most of Europe, which continues to this day.