Why are so many technical aspects of cycling so subjective? I come from an Engineering background and I have a strong interest in science. It has always struck me as odd how so much of cycling is so very subjective. 

As an example, though this is by no means the only thing, the best method of lubricating a chain. Now I appreciate that there is a difference between conditions that it has to operate in but from an engineering viewpoint there will be an optimum type of lubricant and methodology for applying it. Yet most of the advice you can read about it is laced with conjecture and opinion. 

The entire industry appears to be built on arguments that should be resolved with simple repeatable testing. 

Does this type of research simply not exist? or do we just enjoy arguing too much! 

Edited to respond / clarify

As a species we have now sent a number of spacecraft out to the edge of the solar system. One of breakthroughs of New Horizon was getting it to leave earth orbit so quickly. I imagine the number of variables that were contemplated, researched and tested where considerably more complex than the handful that we can consider for a cycle chain. 

The concept of testing isn't to account for every variable, it is to account for individual variables so eventually they can be merged together to get a complete understanding of the underlying system. 

So imagine for a minute a box containing a cassette that can provide some constant friction. Then a powered front ring that turns at x rpm. Every y amount of time the gears are automatically changed.

At that point you can measure how much the chain is stretching, and whatever other criteria you're interested in. 

You could run the same test with different lubricants and get an idea of what lubricant changes which result. 

Once you have that data, you could have a mechanism that drops / throws / shoots z grams of dust / dirty / water / banana at the chain and run the test again. 

At the end of a few chains you're going to be able to categorically say that for riding in mud, a is almost certainly better, for riding in high temperature, b is better. 

It slightly staggers me that we can look at a photograph taken from billions of miles away and say that this is too complicated to figure out. 

Further edited 

It seems that somebody has already come up with that scenario, A guy named Jason Smith at Friction Facts spent $50k building a test lab to test chains. Velo Magazine had a report done on assorted lubes which articulates my point that facts are much better than anecdote. That gives a report that anyone can read and make an informed choice about what would best suit their situation. 

My point in asking this question is that it surprises me that such data isn't used more in conversations about technology and that there isn't more high quality quantitative data about this thing that costs us so much bloody money!
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.