http://i.dailymail.co.uk/i/pix/2011/11/22/article-2064659-0E...
(You can find these graphs with some simple google images searches)
Notice that most cancers, the longevity doesn't change much at all in that ~40 year period. Personally I was expecting some dramatic improvements like the one you allude to (going from 3 to 30 years). It doesn't happen.
I think generally we somehow assume that because there's lots of money being spent on cancer and fancy machines and so on that everything must be better, when in the graphs we only see these various marginal improvements in some specific cancers. I think probably the number one reason for this mismatch is nobody likes to talk about cancer.