I think this is a flawed view of the problem, even with an industry-grade FCS to work with. If you're in the air, you should know how to break out of a stall, belly-land in an emergency, or route around turbulence as it crops up. These things happen, and preventing someone from doing a loop-de-loop won't eliminate a category of failure-modes.
This is something I very much wish would be a reality one day, but you'll be kicking yourself with every incident report that blames bad piloting. One can only hope that they wouldn't risk their own life trusting an untrained pilot.
"failing to control the airplane" is a little like saying everyone dies of heart failure. Yes their heart stopped - but why!?
The real cause is somewhat earlier. Why was a normally competent pilot in a situation where they no longer adequately controlled the aircraft?
Improve avionics - great. Improve situational awareness - really helpful. Handling should be way down the list - it becomes quite intuitive very quickly.
I'd also be deathly afraid of what happens when the automation inevitably fails.
Also, under the upcoming MOSAIC regulations, such airplanes will be LSAs and flyable with a sport pilot license.