I do not agree with this hypothesis.
How often/how many hours are you on the road per day, Alan?
This is probably just your personal experience?
Most of the times, I'm on the road like 8 to 10 hours a day, sometimes even more or 17 hours a day. A lot of city drivings, based on my experiences, however, I do not see most elantra drivers as what you described.
For no turning signals or 10mph under speed limit, I would personally think that there're more like those "new" drivers or "senior" drivers on the road. Everyday, I will usually meet at least one or two drivers ahead of me as you described, it could be a buick driver, a legacy driver, a corolla driver, a mercedes benz..., a SUV..., all kinds of possible, in my opinions. You never know!
On a side note, there's actually a lot of Hyundai Elantras around. The more I look, the more I think they are beautiful. I don't mind considering gettting one if I'm looking for a not-too-big four dr sedan. Another note, most of the new hyundai/kia vehicles are really nice-looking. I don't know where are all the design trends going for toyota, honda, nissan.... . . . maybe Ford has some good-looking cars such as the coming fiesta.
Here's a picture of the coming next generation Hyundai Elantra picture! I would consider buying this if I want a new car in this category. LOOK how hot it is.
If Honda, Toyota and Nissan don't do something nicer...their Sales would go down-south. Hearsay, this car is gonna have more horsepower than current model and again better mpg.
PS: I am not a Hyundai Salesman. If I am, I will probably be able to sell a lot of this.