Quick answer
Wanting is not the same as working. Both men in this verse want things, and only one of them ends up with any.
Read both lines
The verse is precise about where the sluggard fails, and it is not in his desires. He has plenty of those; the word is the ordinary one for craving, and he craves and comes up empty. What separates him from the diligent man is not appetite but the distance between wanting a thing and doing the work the thing requires. The word behind "made rich" carries the sense of being made fat or satisfied, the same term used at 11:25 of the generous person, so what is promised is fullness rather than a fortune.
What it does not mean
This describes a chosen pattern of avoidance, not a diagnosis of anyone's circumstances, and it cannot be read backward. Proverbs itself blocks that two verses from the end of this chapter, saying food goes to waste in the fields of the poor for lack of justice (13:23). A person who is exhausted, ill, disabled, or out of work is not the man in this verse.
Related: Proverbs 13:23 · Proverbs 6:6–11 · Proverbs 11:25
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.