While I entirely concur that MSFS isn't a "simulator" in the sense the industry generally uses, there is a little wrinkle to this statement:
However, that is not a “simulation.” That is programming a “cause” and an “effect.” It looks great – and it may be “fun” – but, its not a true “simulation” the way that word is understood in the aviation industry.
Even "real" simulators use "special effects" at times; it's simply not practical to actually provide a physically meaningful model of some things, and they are generally "tuned" as a cause-and-effect. Things like pre-stall buffet fall into that kind of category.
There's always a conflict between the idealised modelling approach and the crude-but-effective one; it's a case of horses for courses, knowing what the tool will be used for.
Of course you are correct about some of the lesser systems in a simulator being cause-effect modeling. And, when all that is necessary can be accommodated with this approach - great! However, as I am sure you are aware, many simulator manufacturers and vendor suppliers are often at odds with each other in that the manufacturer of the simulator cannot warranty a "black box" provided by an avionics vendor. When that "black box" has a definitive effect on the interoperability of the aerodynamics of the airplane, it becomes critically important to everyone involved; and, as such, the cause-effect approach for something like the avionics interface with flight control computers is simply inadequate.
Naturally, there are limited circumstances when the fully vetted aerodynamic model, systems models, the avionics model, the controls model, etc. may be loaded into something like a lap-top computer. No argument about the accuracy of the resulting displays - but, in those limited cases, the result is not, and should not be considered to be, "flight training."
My fear, that I was attempting to point out in my earlier response, is that some would enter these forums with knowledge gained on MSFS and pretend to know (perhaps, they even
believe that they
do know) what it is they are talking about - when what they say cannot possibly be true beyond the capability of MSFS to accurately replicate the systems and avionics functions as well as the performance and handling qualities of the represented aircraft. I think there are just too many folks growing up with computers and being so reliant on them for accurate information, that some who may find their way into aviation may find it awkward or incomplete or even flat wrong to take something learned on a device like MSFS and put it into practice in an airplane - and expect it to work the way it should in that airplane. And, they may not recognize that error until it becomes evident to them at a critical time. A case in point is the bourgeoning "very light jet" market (at least in the US), where, as some of the advertisements luringly beckon, "All you need is a private certificate with an instrument rating..."
Certainly, I'm not saying that MS couldn't generate something more sophisticated than MSFS; but using aircraft and/or vendor flight test data or other validation data to program the MS product wouldn't, I think, allow it to be sold very profitably for anything approaching what the MSFS product sells for in the game aisle of the local computer store.