Once the magnificent horse played an important role in human society. Without it, mankind wouldn't have 'progressed' as far and as fast as he has (how we measure progress is an interesting topic in itself - perhaps one for another post).
However, once the engine and mass production became established the horse was unceremoniously discarded much like the village blacksmith. Its centuries of service were quickly forgotten by fickle man as wagons made the slow transition to sleek, engine-driven automobiles. The glue factories couldn't handle the number of abandoned horses and vehicles owners talked proudly about how many horsepower their mechanical beasts put out and how fast they could go (especially after a man waving a red light no longer had to run in front of them).
In modern society horses still exist but they occupy a place of little importance except perhaps for the doyen of the racing industry and for a small number of devoted horse lovers who gather at dusty gymkhanas. Of course, horses never created serious greenhouse gases and the resultant global warming nor do they leach carcinogens (which most cars contain) to their riders. And, as the Reuter's photograph above shows, they are still more useful than a car which is suffering from mechanical or electrical troubles.
This horse is pulling a car, its two occupants, the horse driver and a stout wagon. I trust you can appreciate the delicious irony!