Maybe because alternatives to those drugs have been developed but they are still needed by a small number of people who might have a negative interaction with the newer drug, and so you have a smaller number of consumers supporting its production. Keeping these drugs going is expensive. This is especially true if a larger corporation plans to entirely get rid of a medicine and a smaller company buys it. They have to buy the patent and it won't come cheap. They will need the reduced number of people to cover those costs as well, or maybe it's just better if it just doesn't exist.
Maybe shortening patent periods would help.
Maybe because alternatives to those drugs have been developed but they are still needed by a small number of people who might have a negative interaction with the newer drug, and so you have a smaller number of consumers supporting its production. Keeping these drugs going is expensive. This is especially true if a larger corporation plans to entirely get rid of a medicine and a smaller company buys it. They have to buy the patent and it won't come cheap. They will need the reduced number of people to cover those costs as well, or maybe it's just better if it just doesn't exist.
Maybe shortening patent periods would help.
Maybe because alternatives to those drugs have been developed but they are still needed by a small number of people who might have a negative interaction with the newer drug, and so you have a smaller number of consumers supporting its production. Keeping these drugs going is expensive. This is especially true if a larger corporation plans to entirely get rid of a medicine and a smaller company buys it. They have to buy the patent and it won't come cheap. They will need the reduced number of people to cover those costs as well, or maybe it's just better if it just doesn't exist.
Maybe shortening patent periods would help.