We are getting closer!

"And not that the sim would actually be better at teaching an individual to fly RC planes than FMS.
Is that correct?"

If you target is: Take a Trainer 40 into the air, and get it back to the ground, FMS will do "some" job.
If your target is: Take your helicopter (3D airplane, indoor shock flyer ...) into the air without major breakage, FMS will not do the job. You may face breakage and you will pay for in in view of spares.

Safe that money (spares) and invest in a product that will help and avoid crashes. Let me put it this way: you are paying one way or another, in a crash and frustration or for a good sim. Come on, it's our hobby! My neighbours hobby is his dog. Know what he pays for food, acessories and the doctor? The otherone rides his Harley (say: rides - repairs - cleans - rides - repairs ...). Opposite street: sailing boat - (taking a cold shower and draining 100 dollar bills through the sink).

The rules of the market apply here as they do in other fields. If somebody WOULD be able to produce a high quality sim at 30´$ retail, it WOULD be on the market. Forget the cheap PC games. Even a bad PC-Game sells in 100,000+ a year and feeds the programmer, the distribution and the package designers. There arn't that many modellers to come even close to these figures, even if you would lower the price to 5$.

You are looking for entertaining instead of training: Go for IL-2 Sturmvogel or Forgotten battles. Thrilling, entertaining, already available and rather cheap compared to model sims. Get a transmitter to USB interface cable at 30$ and use the outside view - quite nice.

Generally, you are right. There are these "vintage" modellers, understanding modelling as building, handling wood, covering and flying. There are the ARF modellers, not knowing the smell of glue and wood, builing with a srewdriver. Their fun is thrilling 3D, no matter how the aircraft is built. Two different types, one common hobby. No matter what type you like most, flying is what keeps them all together.