why metal roofs make sence

I am really surprised more people keep replacing there roof with shingles as it very short sighted and much more costly in the long run as the best shingle roof only has 110mp rated if perfectly installed which it seldom is and loses wind resistance every year which is why citizens are failing roofs after just 8-9 years as win resistance can drop to 75 mph. so why are metal roofs cheaper when I got my house with a 4 inch of marine foam in the panels dropped  my electic bill by 30 bucks and when I put in a new ac system I dropped a half a ton to 2 ton for my 1200 sf  house and that was almost 20 years ago and my roof today is still rated at 145MPH and will be so for the next 80 year of the expected life of the roof. so while they seem expensive there dirt cheep in the long run