This is about people between 55 and 64 years old at the start of the study.
After 10 years:
The risk of getting colorectal cancer is about 1%.
The risk of dying because of colorectal cancer is about 0.3%.
Getting an invitation the study does not change much. Actually getting a colonoscopy helps more (37% reduction in getting the cancer, no data for dying).
If you read the article thoroughly it explains exactly why your reasoning is incorrect.
Tldr; comparing control group to acceptors group is not right because who accepts and who doesn't isn't random.
We don't know the exact bias introduced but the author theorizes that people who are at higher risk are more likely to accept the invitation(e.g. someone with a colon cancer in family, someone having weird feeling about her tubed as the article calls it., etc.)
You are both right. The study at only 10 years didn't run long enough for us to expect to see much. That is one reason medical studies are hard, we are often interested in changes we could make today that won't matter for decades.
After 10 years:
The risk of getting colorectal cancer is about 1%.
The risk of dying because of colorectal cancer is about 0.3%.
Getting an invitation the study does not change much. Actually getting a colonoscopy helps more (37% reduction in getting the cancer, no data for dying).