The story of the rich man and Lazarus (Luke 17) is often called a parable, but it wasn’t. It was a story to explain the truth so that everyone could understand.
Jesus spoke in parables, not to reveal truth, but to conceal it. In Matthew 13:3-9 Jesus gave the parable of the sower. We who read that today understand the meaning of it because Jesus explained it to his disciples in private. Before he explained it to them, they ask Jesus “why do you speak in Parables?”
Consider Matthew 13:10-16
10 And the disciples came, and said unto him, WHY SPEAKEST THOU UNTO THEM IN PARABLES?
11 He answered and said unto them, Because it is given unto you to know the mysteries of the kingdom of heaven, BUT TO THEM IT IS NOT GIVEN.
12 For whosoever hath, to him shall be given, and he shall have more abundance: but whosoever hath not, from him shall be taken away even that he hath.
13 THEREFORE SPEAK I TO THEM IN PARABLES: because they seeing see not; and hearing they hear not, neither do they understand.
14 And in them is fulfilled the prophecy of Esaias, which saith, By hearing ye shall hear, and shall not understand; and seeing ye shall see, and shall not perceive:
15 For this people’s heart is waxed gross, and their ears are dull of hearing, and their eyes they have closed; lest at any time they should see with their eyes and hear with their ears, and should understand with their heart, and should be converted, and I should heal them.
16 But blessed are your eyes, for they see: and your ears, for they hear. ~ Matthew 13:10-16
In verse 17 -18 Jesus says the following to his disciples: For verily I say unto you, that many prophets and righteous men have desired to see those things which ye see, and have not seen them; and to hear those things which ye hear, and have not heard them. HEAR YE THEREFORE THE PARABLE OF THE SOWER.
Jesus then proceeded to explain the meaning of this parable to his disciples.
Parables were meant to conceal the truth, so that the truth would be revealed to those who would pursue it. When Jesus told stories like the one in Luke 17 (the rich man and Lazarus) nothing was concealed. It was spoken on a level where everyone would understand it, regardless if they accepted or rejected it.