This. Something like 1 in 6 died of TB in the 19th century. TB is still around, but the mortslity rates are nothing like 150 years ago. We don't have smallpox any more, either. It's been a long time since we had an outbreak of cholera in the UK. These days, we have far better public health, health and safety, vaccinations, antibiotics and so on. If you need surgery, anaesthetic knowledge is far better, and just the knowledge and ability to keep things sterile. We all have far more chances of surviving - in the past, a of people simply didn't live long enough to develop cancer.
Also, there were probably misdiagnoses - we didn't have the scanning equipment we do now, and the poor wouldn't have been able to visit the doctor often. It's possible that in the 19th century and earlier, "consumption" wasn't just TB, but also lung cancer and various industrial diseases.
That's not to say plastics and other chemicals we use aren't contributing to certain cancers, but the Victorians used to use arsenic as a food colouring and so on, not to mention lead piping etc. So the food we eat has always been some risk. We've just mostly changed what the risks are.
But I think a lot of it is just not dieing from other stuff.