Cures are not commercially viable.
Treatments that render the disease chronic and that lessen the symptoms while not curing anything are what Big Pharma wants.
Is that why there's so much research going into vaccines?
Youre assuming every pharmaceutical company work can coordinate its efforts to avoid making cures for chronic illnesses when in reality theyre all working against each other. If a company creates a "cure" for a disease, it may lose out on the revenue from chronic medications but it gains the likely astronomic gains from this cure. Not to mention, this leaves every other company with similar chronic medications out in the lurch. So if you were companies B, C, D , E, F, it's in your interest to find the cure faster than the other guy so you're the one who still can make money off this disease.
Not to mention, there are plenty of small biotechs/pharmas that might not have any market penetration into any particular disease but can come up with the magic cure. Thats pure profit without losing any of its previous revenue stream
So is big pharma evil? maybe, but it's not nearly as organized as you think it is.