What impact did Sinclair’s book have on the era of Progressive reform? The Jungle showed that the government was unwilling to make changes because of one person’s attempt at reform. The Jungle made people want to return to the former ways of production they were accustomed to. The Jungle showed that if the public was informed about a certain issue, it had the power to demand reform from the government. The Jungle did not have any great or lasting impact on the era of Progressive reform.