You turn off telomerase, your HSCs stop proliferating, you have no blood cells and game over (a bit exaggerated, but not too much). Cancer is not hard because s

You turn off telomerase, your HSCs stop proliferating, you have no blood cells and game over (a bit exaggerated, but not too much). Cancer is not hard because scientists are stupid, it is hard because it is highly heterogenous and very difficult to even determine common ground, expensive so that study cohorts are allows on the lower end of what is necessary and can be hard to interpret as you have only a single attempt with every patient, mouse model results can be nontransferable to humans etc. We will eventually get it but we will consider it solved after it has been solved for 5 years, not before we even reached a mere 90% cure rate.