Well the problem that scientists are not finding anything that can help to cure cancers, and if you check the new treatments like immunotherapy, and the newest version like using the own trained immune cell of the patient requires an expensive infrastructure. So imagine instead of producing just a chemical compound, all the infrastructure is needed to heal a patient, such as lab technicians, cell culture lab environment... all of that is costly. So yeah it is difficult to reduce the price of this specific treatment. Even for personalized medicine where you are required to sequence the genome of that tumor, it is still costly and I would tell you that the costs of that method have already been reduced in the last 10 years.

So maybe to reduce the cost of the treatment, new cheap treatments need to be discovered.
For example, you probably know BCG vaccine, you probably took it as a baby . An old vaccine for tuberculosis using a weak virus to stimulate our body to create resistance to tuberculosis. It isn't expensive, right? Not a while ago they discovered that using this cheap vaccine directly in bladder cancer in initial stages can bring a good outcome to these patients.

BCG vaccine for specific stages of bladder cancer works very well, so we need to find the cheapest cures for sure for different types of cancer, but it takes some time... Another alternative is to evolve the expensive technologies in a way that won't be expensive in the future, but it is challenging too.