Ain't that the truth. .....especially English Mastiffs, Great Danes, and Irish Wolfhounds. ....often times only living 6 -8 years. I've been lucky with my (150+ lb) Newfoundlands, both living to 12. .....and I miss both of them.
It's so unusual for my breed to live that long, we have a "lucky 13" club for those that make it that many years.