Isn't it because economy studies systems composed of human beings rather than idealized homines economici? What's the point of describing a system that doesn't

Isn't it because economy studies systems composed of human beings rather than idealized homines economici? What's the point of describing a system that doesn't exist in the real world? To give a concrete example, being from the Ostblock, I've lived through the "voucher privatization" that was very much based on the idealized homo economicus model and failed to account for sociological factors. The result was a decade of Mafia-run state. Shrug.