First off, Jesus was speaking to a single archon - the "rich young ruler." Jesus told Peter to come out and walk on the water, but that doesn't mean I need to do the same :) There is nothing in the text to indicate that this is a generalized principle.
Jesus was speaking to one person, and it is interesting how the exchange goes:
If you want to enter life, keep the commandments.”
18 “Which ones?” he inquired.
Jesus replied, “‘You shall not murder, you shall not commit adultery, you shall not steal, you shall not give false testimony, 19 honor your father and mother,’[a] and ‘love your neighbor as yourself.’[b]”
20 “All these I have kept,” the young man said. “What do I still lack?”
Notice that Jesus seems to know what is going on with this guy. Of the last six commandments (typically called the "Second Table" because they talk about how man is to relate to man instead of how man is to relate to God in the "First Table"), Jesus only mentions 5. The missing commandment is significant -
Thou shalt not covet
It is not unreasonable to assume that Jesus knew this was the archon's problem - he was obsessed with wealth. Knowing this young man's problem, he can focus on that.
Also, positionally, this pericope occurs as Jesus is going to Jerusalem to give everything up. Taken from this point of view, it also be taken to show that Jesus himself is totally Good, because Jesus alone is going to be the only one who can truly fulfill this.