Why do you think Harry, Ron, and Hermione looked for the Horcruxes sa pamamagitan ng themselves? Why didn't Dumbledore want them to do it alone?

I think there are a few reasons, though I don't know if they are right! Here are my best guesses:
-Harry had to do it because he was the only one who could defeat Voldemort.
-Ron and Hermione had to go to protect and help Harry, who, in all honesty, cannot walk five paces before landing himself in a world of trouble.
-Ron and Hermione also had to slow Harry down when he searched for the Hallows, because he could only take them at the right time for the right reasons.
-The adults and members of the Order were needed to fight the Death Eaters and protect the Wizarding and Muggle societies.
-Very few people could know about the Horcruxes because if the word went out Voldemort would change their hiding places.