Big pharma is not a monolith. It's an ecosystem of competing companies, big and small. Yes, some of them would cannibalise their own revenues with a cure or a vaccine. But others would stand to improve their revenues. And even those most heavily invested in the "carbohydrate-industrial complex" need to worry about what would happen if a rival came up with a cure or a vaccine. So plenty of pharma firms have incentives to work on a cure or vaccine. As do researchers, charities and governments / public health. And there are many promising scientific lines of enquiry to pursue.