We must let the Bible interpret itself as this has nothing to do with being poor in the physical sense of the word.
Revelation 3:15-18
I know thy works, that thou art neither cold nor hot: I would thou wert cold or hot.
16So then because thou art lukewarm, and neither cold nor hot, I will spue thee out of my mouth.
17Because thou sayest, I am rich, and increased with goods, and have need of nothing; and knowest not that thou art wretched, and miserable, and poor, and blind, and naked: 18I counsel thee to buy of me gold tried in the fire, that thou mayest be rich; and white raiment, that thou mayest be clothed, and that the shame of thy nakedness do not appear; and anoint thine eyes with eyesalve, that thou mayest see.
Being poor in spirit is not about having earthly possessions. This is about the true message of the gospel. Remember, those who does not accept the mark of the beast won't be able to buy or sell. To the world, they are poor in spirit. But in heaven, they are rich. They will inherit the kingdom of heaven!