Capitalism already replaces many citizens with consumers, leaving some behind. Citizens have a say in how money are spent, not just how much money they get. Consumers might get nominal choice in how much money they get, but the choice of how to spend is either forced (e.g. rent or healthcare) or is meaningless (e.g. which brand of car to drive instead of having public transport).

Don't worry, capitalism knows how to make a business out of poor people. Just look at Walmart, and credit cards.