There's a modern concept that people can make money in ways that add to everyone's common wealth. The notion that any number of rich people actually make their money in such ways is suspect, but we do have the concept, and the people of Jesus's time do not.
For them, respectable wealth comes from agricultural land; there's a limited amount of it, and if you get more, your neighbors consequently have less.
As a good 1st Century Jew, can you acquire such wealth from lawful transactions?
Leviticus: (25.23) "The land shall not be sold in perpetuity, for the land is mine; for you are strangers and sojourners with me... (25.35-38) And if your brother becomes poor, and cannot maintain himself with you, you shall maintain him; as a stranger and a sojourner he shall live with you. Take no interest from him or increase, but fear your God, that your brother may live beside you. You shall not lend him your money at interest, nor give him your food for profit. I am the Lord your God, who brought you out of the land of Egypt to give you the land of Canaan, and to be your God."
Deuteronomy: (15.7-9) "If there is among you a poor man, one of your brethren, in any of the towns within your land which the Lord your God gives you, you shall not harden your heart against your poor brother, but you shall open your hand to him, and lend him sufficient for his need, whatever it may be. Take heed lest there be a base thought in your heart, and you say, 'The seventh year, the year of release [of debts among other things] is near,' and your eye be hostile toward your poor brother, and you give him nothing, and he cry to the Lord against you, and it be sin in you."
Some hundred years before, Hillel had found a way around the 7th year limitation, precisely because Jews who had fallen on hard times could not find rich neighbors willing to lend without interest or collateral. Since then, land had increasingly become a commodity to be traded as in pagan cultures, and many families had lost their land to join the ranks of those day-laborers featured in some parables.
William Herzog, in _Jesus, Justice, and the Reign of God_, makes a good case for the possiblity that the whole story is a set-up. Jesus lists the actual crimes the man has not committed, but deliberately omits the commandments about honoring God, which must necessarily have been violated in consolidating so much wealth, and continuing to hold it in the face of his brothers' need. I can't do justice to Herzog's case here, but I agree Jesus is implying that the man has acquired his wealth by violating the spirit of the traditional Jewish Covenant: "Perhaps it has not occured to the rich man that, while he has never killed a man face to face, he has most likely degraded peasant farmers to the status of day laborers, and from the time a peasant becomes a day laborer, devoid of the safety net of the village and with nothing left to sell but his animal energy, to the time he dies of malnuitrition is a matter of a few years at most. Every time he alienates a peasant family from their land he has pronounced a death sentence upon them... Every time that he has blamed his victims for the plight that he and his class have visited upon them, he is bearing false witness against them. It probably has not occured to the rich man that, while he has never mugged anyone on the street and taken their money, he has used the system to rob the poor blind..." For Herzog, Jesus is simply asking the man for restitution.
How to apply this to our own times? Don't we consider it "success" to gain a comfortable life without work--certainly without harsh labor? Which implies that someone else will have to do it. There aren't many people who haven't at some point needed to do something unpleasant for their living--which somehow legitimizes it in our eyes--but how many of us have done our share of the suffering of this world?--or had merely our share of its goods? In principle, more of us than you'd expect would choose to share fairly, but the choice the world offers is "either too much or too little."
But what happens if every good person "sells all that he has, and gives to the poor?" Only bad people would have land, after that? The price of land would fall until poor people could afford some? The bad people who'd bought all the land would have to pay their laborers more than a denarius per day? Everybody would repent?
Obviously we don't have Jesus laying out a rule book here or setting us obstacles we have to jump to "earn" eternal life. But if Jesus is our ruler, how far do we and our institutions measure by this scale?