Why are so many technical aspects of cycling so subjective?
As far as outside testing goes, Friction Facts is an independent company that does exactly what you ask for, testing components against each other to find out what is best, including chains in a variety of conditions (new, re-lubed, wet, dirty, etc).

The top manufacturers presumably have unpublished data, considering that bikes continue to get faster and lighter. This research probably does contain blind spots, and I haven't seen a lot of manufacturer's recommendations about detailed advice on how to maintain a bike.

In addition to this, a quick google search for "research bicycle efficiency" turned up a significant amount of published research about cyclists, but not about bicycles.

I think the reason there are so many arguments on the web about the best way to do anything is that people just like arguing, although you could certainly argue otherwise.