The future is more of the present, give or take a few new technology features and maybe better fuel economy.
If you look around at vehicles on the road today there really aren't many small-mid size cars from the American companies. They're discontinuing these cars because they aren't selling. Kind of like if a restaurant drops their least popular items from the menu it really isn't much of a change and most customers probably wont' even notice.
Next time you're out, look around at cars. You'll notice that the majority of American vehicles are SUV's (or cross overs) and pick up trucks with a few vans and sports cars. But very few small and mid size sedans.
If you look at cars (like actual sedans) almost all of them fall into one of 3 categories:
1. Discount - cars like Kia and Hyundai. These are often the cheapest cars available so they appeal to buyers who need reliable transportation on a tight budget. It helps that they often have small fuel efficient engines which also appeal to the budget-conscious buyers.
2. Japanese/ Reliability - cars such as Toyota, Honda, Subaru and Volkswagen (although VW is German not Japanese). These cars offer at least the perception of reliability and an overall lower cost of ownership over a long period of time. They appeal to practical buyers who don't necessarily need the cheapest car possible but who just want basic transportation without excess cost or the hassle of repairs.
3. Luxury - cars such as Lexus, Infiniti, Audi, Mercedes and BMW. These cars are for people who can pay more for luxury and/or flashy features. Although some of them are built by the same companies in category #2 (for example Toyota makes Lexus) and can be quite reliable.
The Ford Focus and Chevy Caviler cars don't really fit any of these categories and they're really a rare exception on the road these days.
So I really don't think its going to have any major impact on the automotive market when these cars are discontinued.