There is much less chance that a healthy, fit 20 year-old will have a major health problem discovered on a routine physical.
However, as people age, risk facors increase exponentially.
Many conditions have no symptoms that are noticed until the disease is far advanced. Glaucoma, brain tumors and other cancers that could have been caught years before in the early stages are finally discovered far into the process when there is little that can be done.
Particularly bad are those hypertension and diabetics. Generally older men who have avoided doctors will show up after years of damage have taken their toll---and those who survive heart attacks, and strokes, may end up with blindness and circulatory damage---and most often end up dying young.
I think articles such as yours gives foolish advice.