The title of this post seems to be the catchphrase or buzzwords to fit a so-called universal RPG system. Of course, it sounds like the Rosetta Stone to modelling reality for whatever setting it will played in whether by location, genre or theme.
Besides its claims of modelling everything under the sun including the kitchen sink matters, there is also a matter of the level of granularity of the system. This is decided whether te system in question is crunchy or gooey in terms of stats and mechanics.
This post came about from perusing a number of threads on RPG.NET of late. I've seen many cases where gamers would fit setting A into system B which initially fashioned in system C and ad nauseum. Each of the proactives of their fave system would indicate mechanics which best suit or simulate the myriad aspects and details for a setting or idea presented.
Back in the earlier days, the most often go-to system would GURPS which happens to be what it was intended for the purpose, though it entails a major library expansion to accommodate the needed source/genre books to get the most of it. The current trend now is toward so-called "toolkit systems" which just happens to be a big tome of rulesets and a number of suggestions how to make use of this ruleset. HERO system happens to go with this. I was about to mention D20 system as such since it has become all too pervasive in gaming circles which I would call the Microsoft of Gaming systems or in Trekkie parlance, The Borg.
On one spectrum of the rule heavy mechanics of toolkit systems the opposite of it would be the rule lite systems which covers a more fuzzier feel of game mechanics and modelling of reality. BESM is one such system as well as other indie systems to best address nebulous system requirements.
It was like a running lobby for which system rules them all kind of thought to cover whatever genre or setting.
What I have observed in my years of gaming and collecting game systems just boils down to this: a rpg book would be comprised of two sections, the game mechanics and the fluff material. My experience would be to get what the fluff material has to present and then proceed to what system would work best based on experience and ease of play and preparation. That's my two cents about the matter.