I would quantify "quality" as something that stimulates the mind, or expose a person to a concept or idea that they normally wouldn't be exposed to if it wern't for that stimulus.
And how would you measure or express that in mathematical terms?
For example, comparing one game to another, how would you say that "A is 2x better than B"?
When I working for a QA company, a problem was posed to a colleague, and that was to fiqure out a formula for when a software product was good enough to be produced. I'm not sure if he ever come to a conclusion, but I have been thinking about what that formula.
What I came up with was that the ratio of functions to flaws would be needed to determine a baseline for a "ship it" threshold.
Something similar would be needed to compare two games together. A person would need to compare the functionallity of game A to game B, and if game A has X number of new or unique functions, then game A has the potential to be better than B by X. But... I never was too good with math...
So, I guess it comes down to how many people use that product, and are willing to purchase that product. Quality is a refelction of sales some would say, but I'm not sure if I agree with that.. hmmm... tough one...
Any industry that relies on the quality (or a perception of quality) of their product to justify part (or all) of its price will then (in an effort to be more profitable and to quantify the means of their survival) attempt to "measure quality".
It's a greased pig.
Quality is subjective, illusionary, and how people define it changes with the person and the time of day. There was a time when "Made in Japan" meant terrible, almost laughable quality. There was a time when anything made of polymers, plastics of composites were considered inferior to "real materials".
When dealing with consumer goods, consumer tastes, and (yikes!) entertainment? Quality is even more nebulous. What you quantify today, your measure and yardstick is no longer valid tomorrow.