I agree that France is not very representative of the general automobile market, but in Canada for example I would expect most households to start buying a CUV

I agree that France is not very representative of the general automobile market, but in Canada for example I would expect most households to start buying a CUV or SUV as their first car (possibly with AWD). The point is that a classic three-box four-door sedan is not super practical as your only car, and I believe that's true for almost all markets. Americans still bought sedans because the alternatives (wagons, minivans, hatchbacks) were seen as uncool, but CUVs and SUVs don't have this problem at all. So, yes, sedans will still exist but with a fraction of their previous market share, and in this sense sedans will be "dead" (since that's how the article uses the word).