How much experience do you have in oncology? There are millions of breast cancer survivors that might disagree with you. There is also the false assumption that we haven’t made much progress in infectious diseases when, in fact, we have. Tamiflu was launched in 1999. AIDS drugs are light years ahead of where they were 25 years ago. We have effective vaccines for some of history’s worst killer diseases. Gilead has been working on remdesivir since 2016 for Coronaviruses. Hepatitis C is now curable (also thanks to Gilead.)
There is a lot of significant work happening in infectious diseases. However, curing cancer is the holy grail and a pursuit of that is on the same level as pursuing manned space flight. Flying people into space seemed frivolous at the time as well. After all, think of all of the hungry kids would could feed if we redirected Apollo money! However, space flight gave society countless advances that we didn’t foresee at the time. Perhaps we should argue that studying quantum physics is a waste of resources. Or studying astronomy. Or any number of fields where societally-useful breakthroughs are few and far between.
It’s ridiculous to imply that developing cancer drugs should be ditched in favor of developing more infectious disease drugs. We can walk and chew gum at the same time: this isn’t guns or butter.
If we want to apply pure rationality to drugs: let’s stop cancer drug expenditures so we can save more people from malaria, then we could apply that logic to social programs as well: why bother helping the mentally disabled when instead we could direct those funds towards something that provides more economic value to society? A kid with cerebral palsy isn’t going to contribute as much to society as a healthy kid — so why waste resources on that research? Of course it isn’t a waste when it’s your kid. Following that line of reasoning and we ultimately end up with eugenics and society would become a very nasty place indeed.