All those things are awesome but that would massively shake up the world.
What about the millions of people in the healthcare/cancer research field? The people working at the charities? They are potentially out of a job now. What about the resources and housing needs for millions of people not being killed by cancer per year?
A cure would need to be "discovered" or else there would be massive lawsuits from anyone who lost a family member in recent years because of cancer. What about all the new emotional trauma for someone who lost a child when they learn that a cure has been available for decades now?
I agree with you one hundred percent that if a cure is out there it needs to be released. I also agree about doing all the other things you mentioned as well but there would be fall out that would need to be planned for and lessened if possible for all that stuff to happen.