Buying trends have changed, both in type (SUV/CUV vs. sedan) but also between brands and a successful company is able to anticipate and adapt to these changing tastes...as well as help guide them through marketing. Sadly, GM has not been too successful at this for many years. My fear is that, with this decision, when consumer demand invariably shifts away from the S/CUV, the domestics will, to varying degrees be in the same position as they were in '08; late to the game with the wrong product mix. In the end, we will all probably bear some of the costs for this again.
After hearing this sad news, I paid particular attention to sedans during my past two day's driving. There are many sedans around the suburbia here, mostly Hondas, smaller Lexus, lots of Fusions, Audis and BMW. I saw very few GM.
GM is doing the right thing in cost cutting to include ending production of these models, they do not appear to be selling or making the necessary margins, but the mistakes were made long ago that resulted in their losing much of this market segment.