Quick answer
A ruler's standing is measured in people, not in possessions. Without them he has nothing to rule.
Read both lines
The verse states something obvious and easy to forget: authority is a relationship, not a property. A king with no subjects is a man alone, whatever his titles, and the second line calls that a downfall rather than an inconvenience. What makes this more than a political observation is where it lands in a book addressed to ordinary people. Any position that exists because of others is held on those terms, and the chapter has already said at verse 21 what happens to someone who despises the people in front of him.
Related: Proverbs 14:35 · Proverbs 29:14 · Proverbs 14:21
New King James Version®, Copyright © 1982, Thomas Nelson. All rights reserved. Full copyright information. Scripture provided by API.Bible.
Go Deeper
If this verse has been used to put weight on you that it was never carrying, ask about it directly.