Cynical Kyle said:
To be fair to Dumbledore, at that point of time he only had faint suspicions about Voldemort's Horcrux usage [snip]
That's two years before Voldemort was even resurrected.
... shit, actually, you know what? If Dumbledore had just moved his ass, he should have been Horcrux hunting all through year 3, and Voldemort would have been down to just the scar in Harry's face (and Nagini, maybe) by year 4.
As to 'how will he get Voldemort to touch the Prophecy Orb?' Yes, how would you get someone to pick up something that he's already desperately trying to steal? It is a mystery!
Shit, in canon Dumbledore fried his hand on Slytherin's ring, so, that knocks another hole in your 'He's too good a wizard to touch something with a magic booby-trap on it!' theory. Tom's good, but Dumbledore is at least his equal, and he could get caught by a trap like this.
Also Dumbledore had not the slightest idea as to where most of the Horcruxes were.
"I can only guess," said Dumbledore. "For the reasons I have already given, I believe that Lord Voldemort would prefer objects that, in themselves, have a certain grandeur. I have therefore trawled back through VoldemortÆs past to see if I can find evidence that such artifacts have disappeared around him."
"The locket!" said Harry loudly, "HufflepuffÆs cup!"
"Yes," said Dumbledore, smiling, "I would be prepared to bet ù perhaps not my other hand ù but a couple of fingers, that they became Horcruxes three and four. The remaining two, assuming again that he created a total of six, are more of a problem, but I will hazard a guess that, having secured objects from Hufflepuff and Slytherin, he set out to track down objects owned by Gryffindor or Ravenclaw. Four objects from the four founders would, I am sure, have exerted a powerful pull over VoldemortÆs imagination. I cannot answer for whether he ever managed to find anything of RavenclawÆs. I am confident, however, that the only known relic of Gryffindor remains safe."
"Do you think thatÆs why he really wanted to come back to Hogwarts, sir?" said Harry. "To try and find something from one of the other founders?"
"My thoughts precisely," said Dumbledore. "But unfortunately, that does not advance us much further, for he was turned away, or so I believe, without the chance to search the school. I am forced to conclude that he never fulfilled his ambition of collecting four foundersÆ objects. He definitely had two ù he may have found three ù that is the best we can do for now."
"Even if he got something of RavenclawÆs or of GryffindorÆs, that leaves a sixth Horcrux," said Harry, counting on his fingers. "Unless heÆs got both?"
"I donÆt think so," said Dumbledore. "I think I know what the sixth Horcrux is. I wonder what you will say when I confess that I have been curious for a while about the behavior of the snake, Nagini."
-- Harry Potter and the Half-Blood Prince, chapter 23
"The locket!" said Harry loudly, "HufflepuffÆs cup!"
"Yes," said Dumbledore, smiling, "I would be prepared to bet ù perhaps not my other hand ù but a couple of fingers, that they became Horcruxes three and four. The remaining two, assuming again that he created a total of six, are more of a problem, but I will hazard a guess that, having secured objects from Hufflepuff and Slytherin, he set out to track down objects owned by Gryffindor or Ravenclaw. Four objects from the four founders would, I am sure, have exerted a powerful pull over VoldemortÆs imagination. I cannot answer for whether he ever managed to find anything of RavenclawÆs. I am confident, however, that the only known relic of Gryffindor remains safe."
"Do you think thatÆs why he really wanted to come back to Hogwarts, sir?" said Harry. "To try and find something from one of the other founders?"
"My thoughts precisely," said Dumbledore. "But unfortunately, that does not advance us much further, for he was turned away, or so I believe, without the chance to search the school. I am forced to conclude that he never fulfilled his ambition of collecting four foundersÆ objects. He definitely had two ù he may have found three ù that is the best we can do for now."
"Even if he got something of RavenclawÆs or of GryffindorÆs, that leaves a sixth Horcrux," said Harry, counting on his fingers. "Unless heÆs got both?"
"I donÆt think so," said Dumbledore. "I think I know what the sixth Horcrux is. I wonder what you will say when I confess that I have been curious for a while about the behavior of the snake, Nagini."
-- Harry Potter and the Half-Blood Prince, chapter 23
Three clueless kids with nothing but the books in Hermione's purse, who had to stay on the run from an army of Death Eaters besides, were still able to find all the Horcruxes in less than a year... starting with only the clues that Dumbledore had already had.
You'd think that during peacetime, before Voldemort's return, with access to all of Hogwarts library to research and his whole collection of psychological profiling on Voldemort and the ability to just Apparate around freely without having to worry about staying hidden or being attacked by Death Eaters or anything, the most powerful wizard in Great Britain could do in, like, two months, what took the kids like ten months.
So why, if Dumbledore had had all these pensieve memories and clues and everything for years, did he not even start going out and collecting them until year 6? Why the fuck didn't he start in year 3, as soon as he knew for sure that Voldemort had Horcruxes? (And why the fuck was he so careless as to get caught by an idiot booby-trap? PS: Note that this also gives precedent for Voldemort getting bit the same way.)
Answer: It was in the script.