I don't think the parables are just fairy tales constructed for the entertainment of His audience.
No one thinks the parables are just fairy tales constructed for the entertainment of His audience. That is one point at least on which all contributors to this thread are agreed.
The parable of the Good Samaritan was not calculated to entertain. It was more likely to provoke outrage. It was more radical and subversive than most readers of the Gospel realise. Many will see it as exposing the evils of insincere religion and hypocrisy, but it was much more radical than that. It actually exposed the evils of sincere religion.
The Priest and the Levite were sincerely obeying the dictates of the laws forbidding someone dedicated to Jehovah from approaching what might be a dead body (Numbers 6, 9, 19, Haggai 2). But Jesus showed that the Samaritan’s gut instinct (his bowels were moved with compassion) were more in accord with the spirit of the law than the Priest’s and the Levite’s obedience to the letter of the law. Especially radical was the fact that it took a Samaritan, a despised race, to show the Jews how to obey the spirit of their law.
I don’t see much value in discussing whether this actually happened. The story illustrates the point just as forcibly whether it was historical or not.