I have a counterpoint for this
The Elder Wand WAS earned, because of a loophole in its writing. If the owner of the wand was either killed or defeated by an opponent (never specified that it had to be in battle, I do not believe), then ownership of the wand was transferred
One could argue that it wasn't ever Voldemort's because Nagini killed Snape instead of Voldemort himself, but I argue back that, as Nagini was a horcrux and by extension a part of Voldemort, this still counted as Voldemort killing Snape, making him the owner of the wand until Harry defeated him.