I like the way this discussion is headed. I think that Han Solo and Governor - Moff Tarkin's comments about hokey religions (and ancient religion) and ancient weapons - do indeed indicate that the jedi - would seem to be somewhat of a myth or legend. To most of the general inhabitants of the galaxy....
However, Obi Wan Kenobi ...who was a general during the clone wars. Taught by Yoda a great Jedi Knight. Upon meeting the skilled Pilot - Anakin Skywalker, realised how strongly the force was with him and took it upon himself to teach Anakin as a Jedi.
When Ben/Obi Wan Kenobi originally tells Luke about his father being a Jedi Knight - all Ben is trying to do is get Luke to embrace the idea of learning to use the force. He tells Luke that "Oh no you father was never a captain on a merchant vessel...or what ever..." ...pause for effect "He was a Jedi Knight!".
Therefore in Lukes mind (and the audiences) he is the heir of a far more heroic type of character and just the sort of inspiration/motivation that Luke needs in order to leave the farm behind and set off in his fathers footsteps to join the fight against the empire. It also resolves Lukes need to know what happend to his father in very exciting way.
Ben Tells Luke that his uncle made up some some boring story about who his father was to keep him at the farm out of harms way.
I like to think that Ben decided not to tell Luke of the truth that Anakin became Darth vader, to protect him. Which i think is what most people would choose to do until the "young man" becomes old enough to handle the truth. Unfortunately Ben never gets the chance to tell him..... thus the shocking revelation from Vader that comes later.
...think ive rambled off topic for a bit but i like the idea that episodes 1- 3 ...if they are even needed, portray what few followers of the jedi there are as idealist's who follow a strict code of honor.... perhaps more akin to a warrior/samurai practice than monastic/pacifist/worshipfull type religion.
These are rare individuals, that follow the ideals of an ancient cult/order that once numbered into the thousands and protected the republic. But even in this time when Obi Wan is a young man fighting in the clone wars the jedi are considered an ancient religion and followers are scorned much the same way as some people today might scorn other religous individuals due to their belief in a spirituality. Although as we see during the movies their spirituality which is the Force does manifest itself on a physical and on a sub-conscious level.
The Sith are the anti-thesis of the Jedi, a cult that also has a secret following even less well known to the inhabitants of the galaxy than the jedi. Though legends often protray the jedi causing as much harm and strife as the Sith - therefore there is also a fear around the galaxy of force users Jedi or Sith. Although generally the Sith are a purely devil like nature. The Jedi are generally more honorable but not without tales of their fallen heroes.
Therefore when "Return of the Jedi" comes along it is mysteriously a young follower of the Jedi way that restores the balance of light to a beaten people - (with a little help from the rebel alliance)