Simulator upset training has value, but again it's not like being in a real aircraft acheiving more extreme attitudes.
You have a good point, of course. But the big jet loss of control accidents were caused primarily by poor instrument flying skills and in IMC or at night with no visible horizon. In other words, poor instrument flying got the crew into trouble in the first place and the same lack of instrument flying skills caused their inability to recover from extreme attitudes
on instruments in IMC.
Anyone can learn to do daylight VMC aerobatics in a light aircraft certified for aeros but I suggest that very few are in a position or aircraft type to do them on instruments where you cannot peek outside. This is where full flight simulators are better for IMC unusual attitude recovery training
on instruments than a light trainer aircraft.