Not OP, but that is quite a physically demanding job with alot of time in the sun.

Bad on the back and knees, high risk of falling, strokes from heat for older roofers, and the careless ones start throwing hammers around. (I'm not a roofer, but used to be a jack of all trades that sometimes did roofing alongside actual roofers.)

No one wants to roof forever. It's hard and dangerous.

Yes as other have stated the profession is rather hard on your body. I suffered some serious back problems as a result of the manual labor and decided to peruse my interests in engineering instead.