Is sustenance tied to location such that it increases or decreases with a person's travel, and if it does not change, then why travel?

Allah has linked causes to their effects, and striving to seek sustenance is among these causes. This striving may involve travel, for Allah has made the earth subservient and permitted traversing it to seek provision. The Companions and Muslims after them traveled for this purpose. Travel may bring health and wealth, as stated in the Hadith: "Travel, you will be healthy; raid, you will be wealthy." It has also been said that travel dispels worries, gains livelihood, knowledge, and refinement, and brings good companionship.