I disagree, domain age is certainly not a major factor if it is even a factor at all is quite debatable. It doesn’t make sense that Google, or any other search engine, would use the domain age, verses the age of indexed documents. A domain is often re-purposed and it would make Google look silly if a domain about auto insurance ranked high in the SERP for “peach cobbler recipes”, just because it is aged.
It is apparent that aged backlinks pass more link juice due to higher earned trust. I believe the only reason a “real” SEO professional would ever look at domain age is that a domain would have to be old before it could contain aged backlinks. However, just because a domain is old, it doesn’t necessarily mean that it has aged backlinks.
I believe it is not the age of the domains that are important, instead, it is the age of the backlinks, that garner trust, and as a result, greater link juice value is passed. This is exactly why some aged domains when purchased retain PR, while others do not.