Homo economicus means an economic man; a man who wants to acquire wealth-without unnecessary physical labor, and can work towards accomplishing these on his own judgment.
This particular novel- Robinson Crouse has been used by many economic theorists as a tool to illustrate the ideals of homo-economics
Crusoe has come to be seen as a kind of 'economic man',
When seeing human footprint, he appears to be a homo economicus who is overcoming his fear. He is threatened by God, nature, and other human beings
Crusoe faces obstacles of nature and God to attain his own vision. Crusoe at first is terrified at the prospect of isolation, and having to rely upon himself. Yet, he makes his own weapons, bakes bread, and confronts the cannibals. As his confidence grows, he is able to attain his desires using his own power. While not really acquiring wealth in realistic terms, he gains a wealth of knowledge and skills from his ordeal.
Instead of an individual's place in society being determined at birth, and being wholly related to their family name and rank, people entered professions and new social arrangements based not on family or church, but on their work. A relevant example of this is the fact that we don't learn much at all about Robinson's family -- he abandons them in England within the first few pages of the book -- which indicates precisely the degree to which family and other collective relations were taking a back seat to the elaboration of the individual.
The shift from an aristocratic order to a capitalist system was a complicated one, and it would be difficult -- not to
Robinson, Defoe's protagonist, spends the opening sections of the novel in heavy pursuit of money. He readily admits to the reader his reasons for travel. With the money he makes from trading, he's able to buy a plantation in Brazil and begin reaping great profit.
Even romantic love is secondary to economic gain. Living alone on the island, of course, Robinson doesn't have opportunity for romance. But he doesn't worry about it much, either. He has no need for money.