There is a lot of emphasis on Harry becoming the wielder of the Elder Wand once he defeats Draco. However, how do we consider when one is "defeated"? Basically, Harry and Draco have a wrestling match and Harry wins. So now Harry is considered to be the master of the Elder Wand. Yet, after this event, doesn't Harry get "defeated" by the snake, by the Snatchers, and even by Volermort in the forest? Why aren't any of these considered as "defeats"?
The snake almost kills Harry. Harry escapes just in time but his wand breaks. The snatchers chase Harry (and friends) through the forest. Harry and friends basically give up (and Hermione has to even change the appearance of Harry's face). Voldemort almost kills Harry in the forest (or actually does depending on how you look at it). Why aren't any of these considered to be "defeats"?

There's a lot of emphasis on Harry becoming the master of the Elder Wand after he defeats Draco. But what constitutes a “defeat”?

It seems that Harry wins a wrestling match with Draco, so now he’s the master of the Elder Wand.

But lots of other stuff happens to Harry: Nagini almost kills him, and he escapes just in time, but his wand breaks. The Snatchers chase him through the forest. He and his friends practically surrender (and Hermione even tries to disguise Harry). Voldemort almost kills Harry in the Forbidden Forest (or actually does, depending on how you look at it).

Why are none of these considered to be “defeats”?