Some people would prefer quality of life, some want to fight for every last day they can get.

Those are usually the same goal, people on palliative care often live longer. If only 10% of patients respond to a chemo drug, the other 90% are harmed -- frequently resulting in premature death.

Our bias is to not "give up". It causes us to behave irrationally, e.g. giving drugs that have no realistic chance of cure but cause terrible side effects. Doctors also have recall bias -- we remember the one patient that was cured (and assume it was due to the drug, since we prefer the illusion of control), rather than the multitudes who suffered on it for no good reason. A third of patients die in less than a week in hospice and most die within the month. We don't act rationally, and kill people with chemo & aggressive medical therapy rather than let them live out their remaining months/years in relative comfort.

To be fair, I may be biased from being in the ER. I see more patients dying from treatment complications than their cancer, and plenty that were obviously near death when their last treatment was given. Frequently I'm the one that has to break the news that the disease is terminal, which was obvious months prior... but nobody admitted it to the patient/family (+/- some denial on their part) until their life expectancy could be measured in hours.