Its all around one thing.
"what if ....."
What if someone comes back after XX time.
Sure some people will come back after, I dont know, 2 years. But like Thowra said. Most wont even remember their "dead" pet or wont care about them. And so the fact that he/she will simply recreat the acc wont stress them so much. AND is someone leaves from personal reason and is sure to come back then a year time to simply just login for a sec or two wont be a hassel.
I understand that many people got friends that are taking a break.
Still its a closed circle. If they come back, we dont know. If they DO that great really. But if they DONT they its a wast of a good name.
Last, but not least. Working hard for the name. Sure people worked hard to get the name. But what will you tell to a new player?! Work even hard and become a Miracle Worker?!
For them, no matter how hard they work it wont change anything.