The 2016 Summer Olympic Games are opening in Rio de Janeiro amid environmental and health concerns ranging from the Zika virus to polluted competition waters. Brazil, which hosted the World Cup in 2014, is suffering from a deep recession and a political crisis. While the International Olympic Committee touts host cities’ economic legacy, the immense operational challenge of running a mega event creates intense logistical, security, and financial pressures. For ideas on how to improve future Olympics, I spoke with Chris Dempsey, a founding member of the group that defeated Boston’s bid for the 2024 Summer Games. The former Bain & Company consultant argues that recurring cost overruns and mothballed venues highlight the need for the Olympics to change its business model.