If you have a proper decalage angle and the CG to go with it just like your "bad" example quoted here then the model will nose up if the model gets into a dive or nose down if it gets nose high and slows down. Both of which will return the model to it's stable speed ..... Just like a good trainer or general fly around non aerobatic model design SHOULD do.

Yes it does but it also takes a skilled pilot to fly such a model when it is balanced right on the neutral point. Chances are even YOUR model is not on that ragged edge and you are using a slightly forward balance point with some up elevator trim to compensate. If you trim for hands off level and roll it inverted does it still fly hands off? If you need to use a little down elevator to keep it level at that point then you HAVE some decalage even if it's induced by the up elevator trim you have set into the model.

And surprising as it may seem not everyone wants to fly a neutrally stable touchy aerobatic model. Some that are rusty on the thumbs, don't have the reactions any more. or just fly for casual fun to putt around the sky LIKE some pitch stability.