Depends whether you're talking morale values or purpose- TOP competitors in the jumper world and dressage are started in consistant work as young as 2, and jumpers by 3 are going around doing courses.
And, on the flip side - there are also MANY top level Jumpers and Eventers and Dressae Fanatics, who wont start their horses until 4 or 5. And many, work mostly on dressage, and jump maybe once a week - because, a horse only has so much jump in them.
GP Jumpers, would wrather use their horses in the competative ring, to win and make money, than waste them at home.
The horse posted in the OP, is very lovely to look at, I love his coloring and his boldness - but a horse is only worth as much as the fool who is willing to spend.