Other than cynicism, what is the basis for this argument? The economic and social interests of the pharmaceutical companies are to find a cure. If a company came up with a single dose pill that cures colon cancer, they could charge up to the cost of a full course of chemo for that pill and insurance companies would line up to cover it. Go see what has happened with Hep-C and DAAs.
Also, the industry and brand cred that would accrue from being the company that cured cancer would be immense. Think about what that would do for recruiting, influence and access. Ask yourself if Novo-Nordisk is in a worse position today for pretty much curing obesity.
Their argument is just that: 'The reason Zolgensma is so expensive is because that is the price Novartis has decided it is worth because it “dramatically transforms the lives of families affected by this devastating disease”'.
Basically it's "isn't you child's live worth 2.5 million?"
If someone found a one-shot no-side effects cure for a particular type of cancer there's no way they'd price it the same as the full course of chemo, they'd price it at "how much would you pay to be alive again". Insurance companies don't pay shit, their customers do.
But that profit margin would only exist initially. The cure would be much much cheaper than the ongoing treatment once the research pays off, making future margins for smaller yet simultaneously encourage ongoing research to discover a cure to the next disease.
Anyone who claims that there's a 'cure for cancer' somewhere that some company is sitting on for profit betrays their complete lack of understanding of oncology.